Ionic Equilibrium – JEE Main Previous Year Questions with Solutions

JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral.

Simulator

Previous Years AIEEE/JEE Mains Questions

Q. Solid Ba$\left(\mathrm{NO}_{3}\right)_{2}$ is gradully dissolved in a 1.0 × $10^{-4} \mathrm{M} \mathrm{Na}_{2} \mathrm{CO}_{3}$ solution.At what concentration of Ba2+ will a precipitate begin to form? $\left(\mathrm{K}_{\mathrm{SP}} \text { for } \mathrm{Ba} \mathrm{CO}_{3}=5.1 \times 10^{-9}\right)$

(A) $8.1 \times 10^{-8} \mathrm{M}$

(B) $8.1 \times 10^{-7} \mathrm{M}$

(C) $4.1 \times 10^{-5} \mathrm{M}$

(D) $5.1 \times 10^{-5} \mathrm{M}$

[AIEEE-2009,JEE-MAIN(Online)–2013]

Sol. (D)

$5.1 \times 10^{-9}=\left[\mathrm{Ba}^{+2}\right]\left[10^{-4}\right]$

$\left[\mathrm{Ba}^{+2}\right]=5.1 \times 10^{-5} \mathrm{M}$

Q. At 25° C, the solubility producct of $\mathrm{Mg}(\mathrm{OH})_{2}$ is $1.0 \times 10^{-11}$. At which pH, will $\mathrm{Mg}^{2+}$ ions start precipitating in the form of $\mathrm{Mg}(\mathrm{OH})_{2}$ from a solution of 0.001 M $\mathrm{Mg}^{2+}$ ions?

(A) 8                     (B) 9                        (C) 10                             (D) 11

[AIEEE–2010]

Sol. (C)

$10^{-11}=\left[\mathrm{Mg}^{+2}\right]\left[\mathrm{OH}^{-}\right]^{2}$

$10^{-11}=\left(10^{-3}\right)\left[\mathrm{OH}^{-}\right]^{2}$

$\left[\mathrm{OH}^{-}\right]=10^{-4} \quad \mathrm{pOH}=4 \quad \mathrm{pH}=11$

Q. In aqueous solution the ionization constants for carbonic acid are $\mathrm{K}_{1}=4.2 \times 10^{-7}$ and $\mathrm{K}_{2}=4.8$ $\times 10^{-11}$ Select the correct statement for a saturated 0.034 M solution of the carbonic acid :-

(A) The concentration of $\mathrm{H}^{+}$ is double that of $\mathrm{CO}_{3}^{2-}$

(B) The concentration of $\mathrm{CO}_{3}^{2-}$ is $0.034 \mathrm{M}$

(C) The concentration of $\mathrm{CO}_{3}^{2-}$ is greater than that of $\mathrm{HCO}_{3}^{-}$

(D) The concentrations of $\mathrm{H}^{+}$ and $\mathrm{HCO}_{3}^{-}$ are approximately equal

[AIEEE–2010]

Sol. (D)

Q. Solubility product of silver bromide is $5.0 \times 10^{-13}$. The quantity of potassium bromide (molar mass taken as 120 g $\left.\mathrm{mol}^{-1}\right)$ to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is :-

(A) $5.0 \times 10^{-8} \mathrm{g}$

(B) $1.2 \times 10^{-10} \mathrm{g}$

(C) $1.2 \times 10^{-9} \mathrm{g}$

(D) $6.2 \times 10^{-5} \mathrm{g}$

[AIEEE–2010]

Sol. (C)

$\left[\mathrm{Ag}^{+}\right]\left[\mathrm{Br}^{-}\right]=\mathrm{Ksp}$

$[0.05]\left[\frac{\mathrm{W}}{120}\right]=5 \times 10^{-13}$

$\mathrm{w}=\frac{120 \times 5 \times 10^{-13}}{5 \times 10^{-2}}=120 \times 10^{-11}=12 \times 10^{-10}$

$=1.2 \times 10^{-9} \mathrm{g}$

Q. An acid HA ionises as

The pH of 1.0 M solution is 5. Its dissociation constant would be :-

(A) $1 \times 10^{-10}$

(B) 5

(C) $5 \times 10^{-8}$

(D) $1 \times 10^{-5}$

[AIEEE–2011]

Sol. (A)

$\left[\mathrm{H}^{+}\right]=10^{-5}=\mathrm{C}_{\mathrm{o}} \alpha$

$\alpha=10^{-5}$

Q. The $\mathrm{K}_{\mathrm{sp}}$ for $\mathrm{Cr}(\mathrm{OH})_{3}$ is $1.6 \times 10^{-30}$ The molar solubility of this compound in water is :-

(A) $\sqrt[2]{1.6 \times 10^{-30}}$

(B) $\sqrt[4]{1.6 \times 10^{-30}}$

(C) $\sqrt[4]{1.6 \times 10^{-30} / 27}$

(D) $1.6 \times 10^{-30 / 27}$

[AIEEE–2011]

Sol. (C)

$\mathrm{Ksp}=1.6 \times 10^{-30}=27 \mathrm{S}^{4}$

$S^{4}=\left[\frac{1.6 \times 10^{-30}}{27}\right]$

$S=\left[\frac{1.6 \times 10^{-30}}{27}\right]^{1 / 4}$

Q. The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionization constant, Ka of this acid is :-

(A) $1 \times 10^{-7}$

(B) $3 \times 10^{-7}$

(C) $1 \times 10^{-3}$

(D) $1 \times 10^{-5}$

[AIEEE–2012]

Sol. (D)

[\mathrm{HQ}]=0.10 \mathrm{M}

\alpha=10^{-2}

Q. If $\mathrm{K}_{\mathrm{sp}}$ of $\mathrm{CaF}_{2}$ at $25^{\circ} \mathrm{C}$ is $1.7 \times 10^{-10}$ , the combination amongst the following which gives a precipitate of $\mathrm{CaF}_{2}$ is :-

(A) $1 \times 10^{-2} \mathrm{M} \mathrm{Ca}^{2+}$ and $1 \times 10^{-5} \mathrm{M} \mathrm{F}^{-}$

(B) $1 \times 10^{-4} \mathrm{M} \mathrm{Ca}^{2+}$ and $1 \times 10^{-4} \mathrm{M} \mathrm{F}^{-}$

(C) $1 \times 10^{-3} \mathrm{M} \mathrm{Ca}^{2+}$ and $1 \times 10^{-5} \mathrm{M} \mathrm{F}^{-}$

(D) $1 \times 10^{-2} \mathrm{M} \mathrm{Ca}^{2+}$ and $1 \times 10^{-3} \mathrm{M} \mathrm{F}^{-}$

[JEE-MAIN(online)–2012]

Sol. (D)

Q. How many litres of water must be added to 1 litre of an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2 ?

(A) 0.1 L             (B) 0.9 L              (C) 2.0 L            (D) 9.0 L

[AIEEE–2013]

Sol. (D)

\left(10^{-1}\right)(1)=\left(10^{-2}\right)(1+\mathrm{v})

10=\mathrm{v}+1

v = 9L

Q. What would be the pH of a solution obtained by mixing 5 g of acetic acid and 7.5 g of sodium acetate and making the volume equal to 500 mL?

$\left(\mathrm{Ka}=1.75 \times 10^{-5}, \mathrm{pKa}=4.76\right)$

(A) 4.76 < pH < 5.0

(B) pH < 4.70

(C) pH of solution will be equal to pH of acetic acid

(D) pH = 4.70

[JEE-MAIN(Online)–2013]

Sol. (A)

Q. Which one of the following arrangements represents the correct order of solubilities of sparingly soluble salts $\mathrm{Hg}_{2} \mathrm{Cl}_{2}, \mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}, \mathrm{BaSO}_{4}$ and $\mathrm{CrCl}_{3}$ respectively ?

(A) $\left(\frac{\mathrm{K}_{\mathrm{sp}}}{4}\right)^{\frac{1}{3}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{108}\right)^{\frac{1}{3}},\left(\mathrm{K}_{\mathrm{sp}}\right)^{\frac{1}{2}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{27}\right)^{\frac{1}{4}}$

(B) $\left(\mathrm{K}_{\mathrm{ap}}\right)^{\frac{1}{2}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{4}\right)^{\frac{1}{3}},\left(\frac{\mathrm{K}_{\mathrm{gp}}}{27}\right)^{\frac{1}{4}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{108}\right)^{\frac{1}{3}}$

(C) $\left(\mathrm{K}_{\mathrm{sp}}\right)^{\frac{1}{2}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{108}\right)^{\frac{1}{3}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{27}\right)^{\frac{1}{4}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{4}\right)^{\frac{1}{3}}$

$(\mathrm{D})\left(\frac{\mathrm{K}_{\mathrm{sp}}}{108}\right)^{\frac{1}{3}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{27}\right)^{\frac{1}{4}},\left(\mathrm{K}_{\mathrm{sp}}\right)^{\frac{1}{2}},\left(\frac{\mathrm{K}_{\mathrm{sp}}}{4}\right)^{\frac{1}{3}}$

[JEE-MAIN(Online)–2013]

Sol. (A)

Q. NaOH is a strong base. What will be pH of 5.0 × $10^{-2} \mathrm{M}$ NaOH solution ? (log2 = 0.3)

(A) 13.70             (B) 13.00             (C) 14.00             (D) 12.70

[JEE-MAIN(Online)–2013]

Sol. (D)

Q. Zirconium phosphate $\left[\mathrm{Zr}_{3}\left(\mathrm{PO}_{4}\right)_{4}\right]$ dissociates into three zirconium cations of charge +4 and four phosphate anions of charge –3. If molar solubility of zirconium phosphate is denoted by S and its solubility product by $\mathrm{K}_{\mathrm{sp}}$ then which of the following relationship between S and $\mathrm{K}_{\mathrm{sp}}$is correct ?

(A) $\mathrm{S}=\left\{\mathrm{K}_{\mathrm{sp}} / 144\right\}^{1 / 7}$

(B) $\mathrm{S}=\left\{\mathrm{K}_{\mathrm{sp}} /(6912)^{1 / 7}\right\}$

(C) $\mathrm{S}=\left(\mathrm{K}_{\mathrm{sp}} / 6912\right)^{1 / 7}$

(D) $\mathrm{S}=\left\{\mathrm{K}_{\mathrm{sp}} / 6912\right\}^{7}$

[JEE-MAIN(Online)–2014]

Sol. (C)

Q. In some solutions, the concentration of $\mathrm{H}_{3} \mathrm{O}^{+}$ remains constant even when small amounts of strong acid or strong base are added to them. These solutions are known as :-

(A) Colloidal solutions (B) True solutions

(C) Ideal solutions (D) Buffer solutions

[JEE-MAIN(Online)–2014]

Sol. (D)

Q. An aqueous solution contains 0.10 M $\mathrm{H}_{2} \mathrm{S}$ and 0.20 M HCl. If the equilibrium constants for the formation of HS– from H2S is 1.0 × $10^{-7}$ and that of $\mathrm{S}^{2-}$ from $\mathrm{HS}^{-}$ ions is 1.2×$10^{-13}$ then the concentration of $\mathrm{S}^{2-}$ ions in aqueous solution is :

(A) $3 \times 10^{-20}$

(B) $6 \times 10^{-21}$

(C) $5 \times 10^{-19}$

(D) $5 \times 10^{-8}$

[JEE-MAIN–2018]

Sol. (A)

Chemical Equilibrium – JEE Mains Previous Year Questions

JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral.

Simulator

Previous Years AIEEE/JEE Mains Questions

Q. A vessel at 1000 K contains $\mathrm{CO}_{2}$ with a pressure of 0.5 atm. Some of the $\mathrm{CO}_{2}$ is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0.8 atm, the value of K is :-

(1) 0.3 atm (2) 0.18 atm (3) 1.8 atm (4) 3 atm

[AIEEE-2011]

Sol. (3)

Q. The equilibrium constant $\left(\mathrm{K}_{\mathrm{C}}\right)$ for the reaction $\mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{NO}(\mathrm{g})$ at temperature T is $4 \times 10^{-4}$ The value of $\mathrm{K}_{\mathrm{c}}$ for the reaction. $\mathrm{NO}(\mathrm{g}) \longrightarrow 1 / 2 \mathrm{N}_{2}(\mathrm{g})+1 / 2 \mathrm{O}_{2}(\mathrm{g})$ at the same temperature is :-

(1) 50.0

(2) 0.02

(3) $2.5 \times 10^{2}$

(4) $4 \times 10^{-4}$

[AIEEE-2012]

Sol. (1)

$\mathrm{K}_{\mathrm{c}}=\frac{1}{\sqrt{\mathrm{K}_{\mathrm{c}}}}$

Q. 8 mol of $\mathrm{AB}_{3}(\mathrm{g})$ are introduced into a 1.0 $\mathrm{d} \mathrm{m}^{3}$ vessel. If it dissociates as $2 \mathrm{AB}_{3}(\mathrm{g}) \square \quad \mathrm{A}_{2}(\mathrm{g})+3 \mathrm{B}_{2}(\mathrm{g})$

At equilibrium, 2mol of $\mathrm{A}_{2}$ are found to be present. The equilibrium constant of this reaction is :-

(1) 36 (2) 3 (3) 27 (4) 2

[JEE-MAINS(online)-2012]

Sol. (3)

Q. The value of Kp for the equilibrium reaction $\mathrm{N}_{2} \mathrm{O}_{4}(\mathrm{g}) \square 2 \mathrm{NO}_{2}(\mathrm{g})$ is 2 The percentage dissociation of $\mathrm{N}_{2} \mathrm{O}_{4}(\mathrm{g})$ at a pressure of 0.5 atm is

(1) 71 (2) 50 (3) 88 (4) 25

[JEE-MAINS(online)-2012]

Sol. (1)

$\mathrm{K}_{\mathrm{p}}=\frac{(2 \alpha)^{2}}{(1-\alpha)} \times \frac{0.5}{(1+\alpha)}$

Q. $\mathrm{K}_{1}, \mathrm{K}_{2}$ and $\mathrm{K}_{3}$ are the equilibrium constants of the following reactions (I), (II) and (III), respectively

(I) $\mathrm{N}_{2}+2 \mathrm{O}_{2} \square 2 \mathrm{NO}_{2}$

(II) $2 \mathrm{NO}_{2} \square \mathrm{N}_{2}+2 \mathrm{O}_{2}$

(III) $\mathrm{NO}_{2} \square \frac{1}{2} \mathrm{N}_{2}+\mathrm{O}_{2}$

The correct relation from the following is :

(1) $\mathrm{K}_{1}=\sqrt{\mathrm{K}_{2}}=\mathrm{K}_{3}$

(2) $\mathrm{K}_{1}=\frac{1}{\mathrm{K}_{2}}=\frac{1}{\mathrm{K}_{3}}$

$(3) \mathrm{K}_{1}=\frac{1}{\mathrm{K}_{2}}=\mathrm{K}_{3}$

(4)$\mathrm{K}_{1}=\frac{1}{\mathrm{K}_{2}}=\frac{1}{\left(\mathrm{K}_{3}\right)^{2}}$

[JEE-MAINS(online)-2012]

Sol. (4)

Fact

Q. One mole of $\mathrm{O}_{2}(\mathrm{g})$ and two moles of SO2(g) were heated in a closed vessel of one litre capacity at 1098 K. At equilibrium 1.6 moles of $\mathrm{SO}_{3}$ (g) were found. The equilibrium constant $\mathbf{K}_{C}$ of the reaction would be :-

(1) 60 (2) 80 (3) 30 (4) 40

[JEE-MAINS(online)-2012]

Sol. (2)

Q. $\mathrm{N}_{2}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \square 2 \mathrm{NH}_{3}(\mathrm{g}), \mathrm{K}_{1}$

$\mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \square 2 \mathrm{NO}(\mathrm{g}), \mathrm{K}_{2} \quad(\mathrm{B})$

$\mathrm{H}_{2}(\mathrm{g})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{g}) \square \mathrm{H}_{2} \mathrm{O}(\mathrm{g}), \mathrm{K}_{3} \quad(\mathrm{C})$

The equation for the equilibrium constant of the reaction

$2 \mathrm{NH}_{3}(\mathrm{g})+\frac{5}{2} \mathrm{O}_{2}(\mathrm{g}) \square 2 \mathrm{NO}(\mathrm{g})+3 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}),\left(\mathrm{K}_{4}\right)$

in terms of $\mathrm{K}_{1}, \mathrm{K}_{2}$ and $\mathrm{K}_{3}$ is :

(1) $\frac{\mathrm{K}_{1} \mathrm{K}_{3}^{2}}{\mathrm{K}_{2}}$

(2) $\frac{\mathrm{K}_{2} \mathrm{K}_{3}^{3}}{\mathrm{K}_{1}}$

(3) $\frac{\mathrm{K}_{1} \mathrm{K}_{2}}{\mathrm{K}_{3}}$

(4) $\mathrm{K}_{1} \mathrm{K}_{2} \mathrm{K}_{3}$

[JEE-MAINS(online)-2013]

Sol. (2)

Fact

Q. In reaction $\mathrm{A}+2 \mathrm{B} \square 2 \mathrm{C}+\mathrm{D}$, initial concentration of B was 1.5 times of |A|, but at equilibrium the concentrations of A and B became equal. The equilibrium constant for the reaction is

(1)4 (2) 6 (3) 12 (4) 8

[JEE-MAINS(online)-2013]

Sol. (1)

$\mathrm{K}_{\mathrm{c}}=4$

Q. For the decomposition of the compound, represented as

If the reaction is started with 1 mol of the compound, the total pressure at equilibrium would be

(1) $38.8 \times 10^{-2}$ atm

(2) $1.94 \times 10^{-2}$ atm

(3) $5.82 \times 10^{-2}$ atm

(4) $7.66 \times 10^{-2}$ atm

[JEE-MAINS(online)-2014]

Sol. (3)

Q. For the reaction $\mathrm{SO}_{2(\mathrm{g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{g})} \square \mathrm{SO}_{3(\mathrm{g})},$ if $\mathrm{K}_{\mathrm{p}}=\mathrm{K}_{\mathrm{C}}(\mathrm{RT})^{\mathrm{x}}$ where the symbols have usual meaning then the value of x is : (assuming ideality)

( 1)$\frac{1}{2}$

( 2) 1

(3) –1

$(4)-\frac{1}{2}$

[JEE-MAINS 2014]

Sol. (4)

$\mathrm{K}_{\mathrm{p}}=\mathrm{K}_{\mathrm{C}}(\mathrm{RT})^{-\frac{1}{2}}$

Q. The equilibrium constants at 298 K for a reaction $\mathrm{A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D}$ is 100 If the initial concentration of all the four species were 1 M each, then equilibrium concentration of D

(in mol $\mathrm{L}^{-1}$) will be :

(1) 1.182 (2) 0.182 (3) 0.818 (4) 1.818

[JEE-Mains 2016]

Sol. (4)

Atomic Structure – JEE Main Previous Year Questions with Solutions

JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral.

Simulator

Previous Years AIEEE/JEE Mains Questions

Q. In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be located is ($\mathrm{Ch}=6.6 \times 10^{-34} \mathrm{kg} \mathrm{m}^{2} \mathrm{s}^{-1}$, mass of electron,

$\mathrm{e}_{\mathrm{m}}=9.1 \times 10^{-31} \mathrm{kg}$):-

(1) $1.92 \times 10^{-3} \mathrm{m}$

(2) $3.84 \times 10^{-3} \mathrm{m}$

(3) $1.52 \times 10^{-4} \mathrm{m}$

(4) $5.10 \times 10^{-3} \mathrm{m}$

[AIEEE-2009]

Sol. (1)

Q. Calculate the wavelength (in nanometer) associated with a proton moving at $1.0 \times 10^{3} \mathrm{ms}^{-1}$ (Mass of proton = $1.67 \times 10^{-27} \mathrm{kg}$ and $\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}$) :-

(1) 2.5 nm (2) 14.0 nm (3) 0.032 nm (4) 0.40 nm

[AIEEE-2009]

Sol. (4)

$\mathrm{m}_{\mathrm{p}}=1.67 \times 10^{-27}$

$\mathrm{h}=6.63 \times 10^{-34}$

$\mathrm{v}=10^{3}$

$\lambda=\frac{\mathrm{h}}{\mathrm{mv}}=\frac{6.63 \times 10^{-34}}{1.67 \times 10^{-27} \times 10^{3}}$

$=3.97 \times 10^{-7+3}$

$=3.97 \times 10^{-10}$

$=\frac{3.9 \times 10^{-10}}{10^{-9}} \mathrm{nm} \quad=0.40 \mathrm{nm}$

Q. The energy required to break one mole of Cl–Cl bonds in Cl2 is 242 kJ $\mathrm{mol}^{-1}$. The longest wavelength of light capable of breaking a single Cl–Cl bond is

$\left(\mathrm{C}=3 \times 10^{8} \mathrm{ms}^{-1} \text { and } \mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{mol}^{-1}\right)$

(1) 494 nm

(2) 594 nm

(3) 640 nm

(4) 700 nm

[AIEEE-2010]

Sol. (1)

$\mathrm{B.E.}=242 \mathrm{kJ} / \mathrm{mol}$

$\mathrm{E}=\frac{\mathrm{hcN}_{\mathrm{A}}}{\lambda}$

$10^{3} \times 242 \times \lambda=3 \times 10^{8} \times 6.626 \times 10^{-34} \times 6.02 \times 10^{23}$

$\lambda=\frac{3 \times 6.626 \times 6.02 \times 10^{-26+23}}{242}$

$=0.494 \times 10^{-3} \times 10^{-3}$

= 494 nm

Q. Ionisation energy of $\mathrm{He}^{+}$ is $19.6 \times 10^{-18} \mathrm{J}$ atom $^{-1}$. The energy of the first stationary state (n = 1) of $\mathrm{L} \mathbf{i}^{2+}$ is:-

(1) $8.82 \times 10^{-17} \mathrm{J}$ atom $^{-1}$

(2) $4.41 \times 10^{-16} \mathrm{J}$ atom $^{-1}$

(3) $-4.41 \times 10^{-17} \mathrm{J}$ atom $^{-1}$

(4) $-2.2 \times 10^{-15} \mathrm{J}$ atom $^{-1}$

[AIEEE-2010]

Sol. (3)

I.E. $=19.6 \times 10^{-18}$

I.E $\propto \mathrm{z}^{2}$

$\frac{(\mathrm{I.E.})_{\mathrm{Li}^{+2}}}{(\mathrm{I.E.})_{\mathrm{He}}}=\frac{\mathrm{Z}_{\mathrm{Li}}^{2}}{\mathrm{Z}_{\mathrm{He}}^{2}} \quad \mathrm{E}_{1}=\frac{9}{4} \times 19.6 \times 10^{-18}$

$=-4.41 \times 10^{-17}$

Q. The frequency of light emitted for the transition n = 4 to n = 2 of He+ is equal to the transition in H atom corresponding to which of the following

(1) n = 3 to n = 1 (2) n = 2 to n = 1 (3) n = 3 to n = 2 (4) n = 4 to n = 3

[AIEEE-2011]

Sol. (2)

Q. The electrons identified by quantum numbers n and  :-

(a) n = 4 ,  = 1

(b) n = 4,  = 0

(c) n = 3,  = 2

(d) n = 3,  = 1

Can be placed in order of increasing energy as

(1) (a) < (c) < (b) < (d) (2) (c) < (d) < (b) < (a)

(3) (d) < (b) < (c) < (a) (4) (b) < (d) < (a) < (c)

(3) (d) < (b) < (c) < (a) (4) (b) < (d) < (a) < (c)

[AIEEE-2012]

Sol. (3)

(d) < (b) < (c) < (a) Acc. to (n + ) rule.

Q. If the kinetic energy of an electron is increased four times, the wavelength of the de-Broglie wave associated with it would become :-

(1) Two times

(2) Half

(3) One fourth

(4) Four time

[JEE-Main(online2012]

Sol. (2)

$\lambda \propto \frac{1}{\sqrt{\mathrm{KE}}}$

Q. The wave number of the first emission line in the Balmer series of H-Spectrum is :

(R = Rydberg constant) :

(1) $\frac{3}{4} \mathrm{R}$

(2) $\frac{9}{400} \mathrm{R}$

(3) $\frac{5}{36} \mathrm{R}$

(4) $\frac{7}{6} \mathrm{R}$

[JEE-Main(online) 2013]

Sol. (3)

$\bar{v}=\frac{1}{\mathrm{R}}\left(\frac{1}{2^{2}}-\frac{1}{3^{2}}\right)=\frac{5}{36 \mathrm{R}}$

Q. The de Broglie wavelength of a car of mass 1000 kg and velocity 36 km/hr is :

$\left(\mathrm{h}=6.63 \times 10^{-34} \mathrm{J} \mathrm{s}\right)$

(1) $6.626 \times 10^{-31} \mathrm{m}$

(2) $6.626 \times 10^{-34} \mathrm{m}$

(3) $6.626 \times 10^{-38} \mathrm{m}$

(4) $6.626 \times 10^{-30} \mathrm{m}$

[JEE-Main(online) 2013]

Sol. (3)

Q. For which of the following particles will it be most difficult to experimentally verify the de-Broglie relationship?

(1) a dust particle (2) an electron (3) a proton (4) an -particle.

[JEE-Main(online) 2014]

Sol. (1)

Q. If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of $\mathbf{L} \mathbf{i}^{++}$ is :

(1) 13.6 eV (2) 30.6 eV (3) 122.4 eV (4) 3.4 eV

[JEE-Main(online) 2014]

Sol. (2)

B.E. $=3.4 \times 9=30.6 \mathrm{eV}$

Q. Based on the equation

$\Delta \mathrm{E}=-2.0 \times 10^{-18} \mathrm{J}\left(\frac{1}{\mathrm{n}_{2}^{2}}-\frac{1}{\mathrm{n}_{1}^{2}}\right)$

the wavelength of the light that must be absorbed to excite hydrogen electron from level n = 1 to level n $=2$ will be $\left(\mathrm{h}=6.625 \times 10^{-34} \mathrm{Js}, \mathrm{C}=3 \times 10^{8} \mathrm{ms}^{-1}\right)$

(1) $2.650 \times 10^{-7} \mathrm{m}$

(2) $1.325 \times 10^{-7} \mathrm{m}$

(3) $1.325 \times 10^{-10} \mathrm{m}$

(4) $5.300 \times 10^{-10} \mathrm{m}$

[JEE-Main(online) 2014]

Sol. (2)

$\frac{1}{\lambda}=\frac{2 \times 10^{-18}}{\mathrm{hc}}\left[\frac{1}{(1)^{2}}-\frac{1}{(2)^{2}}\right]$

$\Rightarrow \frac{1}{\lambda}=\frac{2 \times 10^{-18}}{6.625 \times 10^{-34} \times 3 \times 10^{8}} \times \frac{3}{4}$

$\Rightarrow \lambda=\frac{2 \times 6.625 \times 10^{-34} \times 10^{8}}{10^{-18}}$

$=13.25 \times 10^{-8}$

$=1.325 \times 10^{-7} \mathrm{m}$

Q. If

be the threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from the metal surface is

[JEE-Main(online) 2014]

Sol. (1)

$\mathrm{E}=\phi+\frac{1}{2} \mathrm{mv}^{2}$

$\Rightarrow \frac{\mathrm{hc}}{\lambda}=\frac{\mathrm{hc}}{\lambda_{0}}+\frac{1}{2} \mathrm{mv}^{2}$

$\Rightarrow \mathrm{v}^{2}=\frac{2 \mathrm{hc}}{\mathrm{m}}\left[\frac{1}{\lambda}-\frac{1}{\lambda_{0}}\right] \Rightarrow \mathrm{v}=\sqrt{\frac{2 \mathrm{hc}}{\mathrm{m}}\left[\frac{1}{\lambda}-\frac{1}{\lambda_{0}}\right]}$

$\Rightarrow \mathrm{v}=\sqrt{\frac{2 \mathrm{hc}}{\mathrm{m}}\left[\frac{\lambda_{0}-\lambda}{\lambda \lambda_{0}}\right]}$

Q. Ionization energy of gaseous Na atoms is 495.5 $\mathrm{kjmol}^{-1}$ . The

lowest possible frequency of light that ionizes a sodium atom is

$\left(\mathrm{h}=6.626 \times 10^{-34} \mathrm{Js}, \mathrm{N}_{\mathrm{A}}=6.022 \times 10^{23} \mathrm{mol}^{-1}\right)$

(1) $3.15 \times 10^{15} \mathrm{s}^{-1}$

(2) $4.76 \times 10^{14} \mathrm{s}^{-1}$

(3) $1.24 \times 10^{15} \mathrm{s}^{-1}$

(4) $7.50 \times 10^{4} \mathrm{s}^{-1}$

[JEE-Main(online) 2014]

Sol. (3)

$\Delta \mathrm{E}=\mathrm{hv}$

$\mathrm{v}=\frac{\Delta \mathrm{E}}{\mathrm{h}}$

$\mathrm{v}=\frac{495.5 \times 10^{3} \mathrm{Joule}}{6.023 \times 10^{23}} \times \frac{1}{6.626 \times 10^{-34}}$

$\mathrm{v}=1.24 \times 10^{15} \mathrm{sec}^{-1}$

Q. Which of the following is the energy of a possible excited state of hydrogen?

(1) –3.4 eV (2) +6.8 eV (3) +13.6 eV (4) –6.8 eV

[JEE-Main(offline) 2015]

Sol. (1)

For H-atom, (Z = 1)

$\mathrm{E}_{\mathrm{n}}=-13.6 \times \frac{\mathrm{Z}^{2}}{\mathrm{n}^{2}} \mathrm{eV}$

\begin{aligned} \therefore \text { So for } \mathrm{E}_{1} &=-13.6 \mathrm{eV} \\ \mathrm{E}_{2} &=-3.4 \mathrm{eV} \end{aligned}

Q. A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron respectively, then the value of $\mathrm{h} / \lambda$ (where $\lambda$is wavelength associated with electron wave) is given by :

(1) $\sqrt{2 \mathrm{meV}}$

(2) mev

(3) $2 \mathrm{meV}$

(4) $\sqrt{\mathrm{meV}}$

[JEE-Main 2016]

Sol. (1)

As electron of charge ‘e’ is passed through ‘V’ volt, kinetic energy of electron becomes = ‘eV’

As wavelength of $e^{-}$ wave = $(\lambda)=\frac{\mathrm{h}}{\sqrt{2 \mathrm{m} \cdot \mathrm{K} \cdot \mathrm{E}}}$

$\lambda=\frac{\mathrm{h}}{\sqrt{2 \mathrm{meV}}}$

$\therefore \quad \frac{\mathrm{h}}{\lambda}=\sqrt{2 \mathrm{meV}}$

Q. The radius of the second Bohr orbit for hydrogen atom is :

(Planks const. $\mathrm{h}=6.6262 \times 10^{-34} \mathrm{Js}$; mass of electron $=9.1091 \times 10^{-31} \mathrm{kg} ;$ charge of electron $\mathrm{e}=$ $1.60210 \times 10^{-19} \mathrm{C}:$ permittivity of vaccuml $\left.\epsilon_{0}=8.854185 \times 10^{-12} \mathrm{kg}^{-1} \mathrm{m}^{-3} \mathrm{A}^{2}\right)$

[JEE-Main 2017]

Sol. (4)

Radius of $\mathbf{n}^{\mathrm{th}}$ Bohr orbit in H-atom

Radius of II Bohr orbit $=0.53 \times(2)^{2}$

Structural Isomerism – JEE Main Previous Year Questions with Solutions

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Previous Years AIEEE/JEE Mains Questions

Q. The alkene that exhibits geometrical isomerism is :-

(1) 2–butene

(2) 2–methyl–2–butene

(3) Propene

(4) 2–methyl propene

[AIEEE-2009]

Sol. (1)

Q. The number of stereoisomers possible for a compound of the molecular formula

CH3–CH=CH–CH(OH)–Me is :-

(1) 4             (2) 6              (3) 3             (4) 2

[AIEEE-2009]

Sol. (1)

exhibits both geometrical as well as optical isomerism.

Cis – R

Trans – R

Cis – S

Trans – S

Q. Out of the following, the alkene that exhibits optical isomerism is :

(1) 2-methyl-2-pentene

(2) 3-methyl-2-pentene

(3) 4-methyl-1-pentene

(4) 3-methyl-1-pentene

[AIEEE-2010]

Sol. (4)

Q. Identify the compound that exhibits tautomerism :-

(1) 2-Pentanone (2) Phenol (3) 2-Butene (4) Lactic acid

[AIEEE-2011]

Sol. (1)

Q. The IUPAC name of the following compounds is :

(1) (Z) – 5 – hepten – 3 – yne

(2) (Z) – 2 – hepten – 4 – yne

(3) (E) – 5 – hepten – 3 – yne

(4) (E) – 2 – hepten – 4 – yne

[JEE-Main-2012]

Sol. (4)

Q. Dipole moment is shown by :-

(1) trans-2, 3-dichloro- 2-butene

(2) 1, 2-dichlorobenzene

(3) 1, 4-dichlorobenzene

(4) trans-1, 2-dinitroethene

[JEE-Main 2012]

Sol. (2)

Q. Maleic acid and fumaric acids are :-

(1) Tautomers

(2) Chain isomers

(5) Geometrical isomers

(4) Functional isomers

[JEE-Main 2012]

Sol. (3)

Q. Monocarboxylic acids are functional isomers of :

(1) Esters (2) Amines (3) Ethers (4) Alcohols

[JEE-Main 2013]

Sol. (1)

Monocarboxylic acid and Esters $(-\mathrm{COO}-)$ has same general $(-\mathrm{COOH}) .$

Formula $\left[\mathrm{C}_{\mathrm{n}} \mathrm{H}_{2 \mathrm{n}} \mathrm{O}_{2}\right]$ but different FG, so are called functional group isomer.

Q. Arrange in the correct order of stability (decreasing order) for the following molecules:

[JEE-Main 2013]

Sol. (3)

Q. For which of the following molecule significant $\mu \neq 0$

[JEE-Main 2014]

Sol. (2)

Due to presence of $\ell . \mathrm{p}_{(\mathrm{s})}$ on oxygen and sulphur atom which are out of plane hence

Oxidation & Reduction – JEE Main Previous Year Questions with Solutions

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Q. Which of the following will change the colour of acidic dichromate solution.

[JEE-MAINS 2013]

Sol. (A)

Q.

[JEE-MAINS 2013]

Sol. (C)

Q.

[JEE-MAINS 2013]

Sol. (A)

Q. The most suitable reagent for the conversion of $\mathrm{R}-\mathrm{CH}_{2}-\mathrm{OH} \rightarrow \mathrm{R}-\mathrm{CHO}$ is :-

(A) $\mathrm{CrO}_{3}$

(B) PCC (Pyridinium chlorochromate)

(D) $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$

[JEE-MAINS 2014]

Sol. (B)

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Q. The IUPAC name of neopentane is :-

(1) 2–methylpropane

(2) 2, 2–dimethylbutane

(3) 2–methylbutane

(4) 2, 2–dimethylpropane

[AIEEE -2009]

Sol. (4)

Q. The IUPAC name of the compound is :-

(1) 1, 2-Epoxy propane

(2) Propylene oxide

(3) 1, 2–Oxo propane

(4) 1, 2–Propoxide

[AIEEE -2012(online]

Sol. (1)

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Q. The main product of the following reaction is

[AIEEE-2010]

Sol. (2)

Q. One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is :-

(1) Ethene

(2) Propene

(3) 1-Butene

(4) 2-Butene

[AIEEE-2010]

Sol. (4)

Q. Ozonolysis of an organic compound gives formaldehyde as one of the products. This confirms the presence of :-

(1) an isopropyl group

(2) an acetylenic triple bond

(3) two ethylenic double bonds

(4) a vinyl group

[AIEEE-2011]

Sol. (4)

Q. Ozonolysis of an organic compound ‘A’ produces acetone and propionaldehyde in equimolar mixture. Identify ‘A’ from the following compounds :-

(1) 2-Methyl-1-pentene

(2) 1-Pentene

(3) 2-Pentene

(4) 2-Methyl-2-pentene

[AIEEE-2011]

Sol. (4)

Q. 2–Hexyne gives trans–2–Hexene on treatment with :-

[AIEEE-2012]

Sol. (3)

Q. In the given transformation, which of the following is the most appropriate reagent ?

[AIEEE-2012]

Sol. (2)

Q. The major organic compound formed by the reaction of 1, 1, 1–trichloroethane with silver powder is :-

(1) 2-Butyne

(2) 2-Butene

(3) Acetylen

(4) Ethene

[Jee-Main offline 2013]

Sol. (1)

Q. The number and type of bonds in $\mathrm{C}_{2}^{2-}$ ion in $\mathrm{CaC}_{2}$ are:

(1) Two $\sigma$ bonds and one $\pi$ – bond

(2) Two $\sigma$ bonds and two $\pi$ – bonds

(3) One $\sigma$ bond and two $\pi$ – bonds

(4) One $\sigma$ bond and one $\pi-$ bond

[Jee-Main offline 2014]

Sol. (3)

$\mathrm{Ca}^{+2}[\mathrm{C} \equiv \mathrm{C}]^{-2}$

Q. In the hydroboration – oxidation reaction of propene with diborane, $\mathrm{H}_{2} \mathrm{O}_{2}$ and NaOH, the organic compound formed is :

(1) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}$

( 2)$\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}$

(3) $\mathrm{CH}_{3} \mathrm{CHOHCH}_{3}$

(4) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$

[Jee-Main offline 2014]

Sol. (1)

Q. Which one of the following class of compounds is obtained by polymerization of acetylene ?

(1) Poly-ene

(2) Poly-yne

(3) Poly-amide

(4) Poly-ester

[Jee-Main offline 2014]

Sol. (2)

Q. The gas liberated by the electrolysis of Dipotassium succinate solution is :

(1) Ethyne

(2) Ethene

(3) Propene

(4) Ethane

[Jee-Main offline 2014]

Sol. (2)

Q. The reagent needed for converting

(1) $\mathrm{H}_{2} /$ lindlar Cat.

(2) Cat. Hydrogenatio

(4) LiNH $_{3}$

[Jee-Main offline 2014]

Sol. (4)

Q. on mercuration- demercuration produces the major product :-

[Jee-Main offline 2014]

Sol. (1)

Rearrangement of carbocation formed is not possible due to formatiion of cyclic non-classical carbocation.

Q. The major product obtained in the photo catalysed bromination of 2-methylbutane is :-

(1) 2-bromo-2-methylbutane

(2) 2-bromo-3-methylbutane

(3) l-bromo-2-methylbutane

(4) l-bromo-3-methylbutane

[Jee-Main offline 2014]

Sol. (1)

Q. In the presence of peroxide, HC and HI do not give anti-Markownikoff s addition to alkenes because

(1) All the steps are exothermic in HCl and HI

(2) One of the steps is endothermic in HCl and HI

(3) HCl is oxidizing and the HI is reducing

(4) Both HCl and HI are strong acids

[Jee-Main offline 2014]

Sol. (2)

relectivity ratio for bromination is

$1^{\circ}: 2^{\circ}: 3^{\circ}: 1: 82: 1600$

Hence $3^{\circ}$ product will be major product.

Q. Which compound would give 5-keto-2-methyl hexanal upon ozonlysis?

[Jee-Main offline 2015]

Sol. (4)

Q. The trans-alkenes are formed by the reduction of alkynes with :

(1) $\mathrm{NaBH}_{4}$

(2) Na/liq. NH $_{3}$

(3) Sn–HCl

(4) $\mathrm{H}_{2}-\mathrm{Pd} / \mathrm{C}, \mathrm{BaSO}_{4}$

[Jee-Main offline 2018]

Sol. (2)

Birch reduction is anti addition. So trans alkene will be produced.

Halogen Derivative – JEE Main Previous Year Questions with Solutions

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Previous Years AIEEE/JEE Mains Questions

Q. Which of the following on heating with aqueous KOH, produces acetaldehyde ?

(1) $\mathrm{CH}_{2} \mathrm{ClCH}_{2} \mathrm{Cl}$

(2) $\mathrm{CH}_{3} \mathrm{CHCl}_{2}$

(3) $\mathrm{CH}_{3} \mathrm{COCl}$

(4) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}$

[AIEEE-2009]

Sol. (1)

Q. Consider the following bromides :-

The correct order of $\mathrm{S}_{\mathrm{N}}^{1}$ reactivity is

(1) A > B > C

(2) B > C > A

(3) B > A > C

(4) C > B > A

[AIEEE-2010]

Sol. (2)

Q. The major product of the following reaction is :

[JEE-MAIN2018]

Sol. (1)

Reaction is dehydrohalogenation

$\mathrm{E}^{2}$-elimination reaction. Elimination takes place in single step and proceed by formation of transition state from anti position.

Q. The major product formed in the following reaction is :

[JEE-MAIN2018]

Sol. (3)

It is nucleophilic substitution reaction.

General Organic Chemistry – JEE Main Previous Year Questions with Solutions

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Previous Years AIEEE/JEE Mains Questions

Q. Arrange the carbanions, $\left(\mathrm{CH}_{3}\right)_{3} \overline{\mathrm{C}}, \overline{\mathrm{C}} \mathrm{Cl}_{3},\left(\mathrm{CH}_{3}\right)_{2} \overline{\mathrm{C}} \mathrm{H}, \mathrm{C}_{6} \mathrm{H}_{5} \overline{\mathrm{C}} \mathrm{H}_{2}$ , in order of their

decreasing stability

[AIEEE-2009]

Sol. (1)

Q. The non aromatic compound among the following is :-

[AIEEE-2011]

Sol. (1)

Q. ortho-Nitrophenol is less soluble in water than p– and m– Nitrophenols because :-

(1) Melting point of o–Nitrophenol is lower than those of m– and p– isomers

(2) o–Nitrophenol is more volatile in steam than those of m– and p– isomers

(3) o–Nitrophenol shows Intramolecular H–bonding

(4) o–Nitrophenol shows Intermolecular H–bonding

[AIEEE-2012]

Sol. (3)

Q. Which of the following compounds are antiaromatic :-

(1) (1) and (6) (2) (2) and (5) (3) (1) and (5) (4) (5) and (6)

[AIEEE-2012(Online)]

Sol. (4)

Q. Among the following the molecule with the lowest dipole moment is :-

(1) $\mathrm{CHCl}_{3}$

(2) $\mathrm{CH}_{2} \mathrm{Cl}_{2}$

(3) $\mathrm{CCl}_{4}$

(4) $\mathrm{CH}_{3} \mathrm{Cl}$

[AIEEE-2012(Online)]

Sol. (3)

Q. The order of stability of the following carbocations

(1) III > II > I

(2) II > III > I

(3) I > II > III

(4) III > I > II

[JEE-MAIN-2013]

Sol. (4)

Q. For which of the following molecule significant $\mu^{1} 0$

(1) Only (3) (2) (3) and (4) (3) Only (1) (4) (1) and (2)

[JEE-MAIN-2014]

Sol. (2)

So dipole moment per mole (containing $\mathrm{N}_{\mathrm{A}}$ molecules) is non

zero. Some concept applicable for option (4) .

Q. The correct order of increasing basicity of the given conjugate base $\left(\mathrm{R}=\mathrm{CH}_{3}\right.$) is :-

$(1) \mathrm{RCO} \overline{\mathrm{O}}<\mathrm{HC} \equiv \overline{\mathrm{C}}<\overline{\mathrm{N}} \mathrm{H}_{2}<\overline{\mathrm{R}}$

(2) $\mathrm{RCO} \overline{\mathrm{O}}<\mathrm{HC} \equiv \overline{\mathrm{C}}<\overline{\mathrm{R}}<\overline{\mathrm{N}} \mathrm{H}_{2}$

(3) $\quad \overline{\mathrm{R}}<\mathrm{HC} \equiv \overline{\mathrm{C}}<\mathrm{RCO} \overline{\mathrm{O}}<\overline{\mathrm{N}} \mathrm{H}_{2}$

(4) $\mathrm{RCO} \overline{\mathrm{O}}<\overline{\mathrm{N} H}_{2}<\mathrm{HC} \equiv \overline{\mathrm{C}}<\overline{\mathrm{R}}$

[AIEEE-2010]

Sol. (1)

Basic strength $\propto \frac{1}{\text { Stability of conjugate base }}$

Q. The strongest acid amongst the following compounds is ?

(1) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{CO}_{2} \mathrm{H}$

(2) $\mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH}$

(3) $\mathrm{CH}_{3} \mathrm{COOH}$

(4) HCOOH

[AIEEE-2011]

Sol. (1)

(Acidity a –I effect)

Q. The correct order of acid strength of the following compounds :-

A. Phenol B. p-Cresol C. m-Nitrophenol D. p- Nitrophenol

(1) C > B > A > D (2) D > C > A > B

(3) B > D > A > C (4) A > B > D > C

[AIEEE-2011]

Sol. (2)

Q. In the following compounds :

the order of basicity is as follows :

(1) IV > III > II > I

(2) II > III > I > IV

(3) I > III > II > IV

(4) III > I > II > IV

[JEE(Main)-2012]

Sol. (3)

Q. The most basic compound among the following is :-

(1) Acetanilide

(2) Benzylamine

(3) p-Nitro aniline

(4) Aniline

[JEE(Main)-2012]

Sol. (2)

Basicity $\propto \frac{1}{\text { Resonance of lone pair e }}$

Q. The order of basicity of amines in gaseous state is :-

(1) $3^{\circ}>2^{\circ}>\mathrm{NH}_{3}>1^{\circ}$

(2) $1^{\circ}>2^{\circ}>3^{\circ}>\mathrm{NH}_{3}$

(3) $\mathrm{NH}_{3}>1^{\circ}>2^{\circ}>3^{\circ}$

(4) $3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{NH}_{3}$

[JEE(Main)-2013]

Sol. (4)

Basicity $\propto+I$ effect

Q. Arrange the following compounds in order of decreasing acidity :

(1) II > IV > I > III

(2) I > II > III > IV

(3) III > I > II > IV

(4) IV > III > I > II

[JEE(Main)-2013]

Sol. (3)

Acidity $\propto-\mathrm{I} /-\mathrm{R} \propto \frac{1}{+\mathrm{I} /+\mathrm{R}}$

Q. The conjugate base of hydrazoic acid is :-

(1) $\mathrm{HN}_{3}^{-}$

(2) $\mathrm{N}_{3}^{-}$

(3) $\mathrm{N}_{2}^{-}$

(4) $\mathrm{N}^{-3}$

[JEE(Main)-2014]

Sol. (2)

$\left(\mathrm{HN}_{3} \longrightarrow \mathrm{N}_{3}+\mathrm{H}^{+}\right)$

Q. Which one of the following compounds will not be soluble in sodium bicarbonate ?

(1) Benzene sulphonic acid

(2) Benzoic acid

(3) o-Nitrophenol

(4) 2, 4, 6 – Trinitrophenol

[JEE(Main)-2014]

Sol. (2)

Due to ortho effect

Q. Considering the basic strength of amines in aqueous solution, which one has

the smallest $\mathrm{pK}_{\mathrm{b}}$ value ?

(1) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{N}$

(2) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$

(3) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}$

(4) $\mathrm{CH}_{3} \mathrm{NH}_{2}$

[JEE(Main)-2014]

Sol. (3)

\begin{aligned} \therefore \text { Due to solvation and inductive effect } \\ 2^{\circ}>1^{\circ}>3^{\circ}>0^{\circ} & \mathrm{R}=-\mathrm{CH}_{3} \end{aligned}

Q. Among the following oxoacids, the correct decreasing order of acid strength is :

(1) $\mathrm{HClO}_{4}>\mathrm{HClO}_{3}>\mathrm{HClO}_{2}>\mathrm{HOCl}$

(2) $\mathrm{HClO}_{2}>\mathrm{HClO}_{4}>\mathrm{HClO}_{3}>\mathrm{HOCl}$

(3) $\mathrm{HOCl}>\mathrm{HClO}_{2}>\mathrm{HClO}_{3}>\mathrm{HClO}_{4}$

(4) $\mathrm{HClO}_{4}>\mathrm{HOCl}>\mathrm{HClO}_{2}>\mathrm{HClO}_{3}$

[JEE(Main)-2014]

Sol. (1)

$\therefore$ Acidic $\propto$ more E.R.S. of conjugate base

Q. The increasing order of basicity of the following compounds is :

(1) (1) < (1) < (3) < (4)

(2) (1) < (1) < (4) < (3)

(3) (4) < (2) < (1) < (3)

(4) (1) < (2) < (3) < (3)

[JEE(Main)-2018]

Sol. (2)

Order of base nature depends on electron donation tendency.

In compoundnitrogen is sp2 hybridized so least basic among all given compound.

compoundis very strong nitrogeneous organic base as lone pair of one nitrogen

delocalize in resonance and make another nitrogen negativly charged and conjugate acid have

two equivalent resonating structure.

Thus it is most basic in given compouds.(secondary amine) more basic than (primary amine)

Environmental Chemistry – JEE Main Previous Year Questions with Solutions

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Q. 29.5 mg of an organic compound containing nitrogen was digested according to Kjeldahl’s method and the evolved ammonia was absorbed in 20 mL of 0.1 M HCl solution. The excess of the acid required 15 mL of 0.1 M NaOH solution for complete neutralization. The percentage of nitrogen in the compound is :-

(1) 29.5          (2) 59.0          (3) 47.4            (4) 23.7

[AIEEE-2010]

Sol. (4)

Equation of $\mathrm{NH}_{3}$

$=(0.1 \times 20)-(0.1 \times 15)=0.5$

wt. of $\mathrm{NH}_{3}$

$=0.5 \times 17=8.5 \mathrm{mg}$

wt. of $^{\prime} N^{\prime}$

$=\frac{14}{17} \times 8.5 \mathrm{mg}=7 \mathrm{mg}$

$\%$ of $^{\prime} \mathrm{N}^{\prime}=\frac{7}{29.5} \times 100=23.7$

Q. The recommended concentration of fluoride ion in drinking water is up to 1 ppm as fluoride ion is required to make teeth enamel harder by converting $\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{Ca}(\mathrm{OH})_{2}\right]$ to :

(1) $\left[3\left(\mathrm{CaF}_{2}\right) \cdot \mathrm{Ca}(\mathrm{OH})_{2}\right]$

(2) $\left[3\left(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{CaF}_{2}\right]\right.$

(3) $\left[3\left(\mathrm{Ca}(\mathrm{OH})_{2}\right] \cdot \mathrm{CaF}_{2}\right]$

(4) $\left[\mathrm{CaF}_{2}\right]$

[JEE-Mains -2018]

Sol. (2)

$\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{Ca}(\mathrm{OH})_{2}\right]+2 \mathrm{F}^{\ominus} \longrightarrow$

(drinking water upto $1 \text { ppm })$

$\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{CaF}_{2}\right]+2 \mathrm{OH}^{\ominus}$

(Harder teeth enamel)

Aromatic Compound – JEE Mains Previous Year Questions

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Previous Years AIEEE/JEE Mains Questions

Q. In the chemical reactions,

the compounds ‘A’ and ‘B’ respectively are :-

(1) Nitrobenzene and chlorobenzene

(2) Nitrobenzene and fluorobenzene

(3) Phenol and benzene

(4) Benzene diazonium chloride and fluorobenzene

[AIEEE-2010]

Sol. (4)

Q. In the chemical reactions

(1) Fluorobenzene and phenol

(2)Benzene diazonium chloride and benzonitrile

(3) Nitrobenzene and chlorobenzene

(4) Phenol and bromobenzene

[AIEEE-2011]

Sol. (2)

Q. An organic compound A upon reacting with $\mathrm{NH}_{3}$ gives B. On heating, B gives C. C in presence of KOH reacts with $\mathrm{Br}_{2}$ to give $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2} . \mathrm{A}$ is :-

(1) $\mathrm{CH}_{3} \mathrm{COOH}$

(2) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH}$

(4) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}$

[JEE(Main)-2013]

Sol. (4)

Q. The gas leaked from a storage tank of the Union Carbide plant in Bhopal gas tragedy was:-

(1) Methylisocyanate

(2) Methylamine

(3) Ammonia

(4) Phosgene

[JEE(Main)-2013]

Sol. (1)

Q. On heating an aliphatic primary amine with chloroform and ethanolic potassium hydroxide, the organic compound formed is :

(1) An alkyl cyanide

(2) An alkyl isocyanide

(3) An alkanol

(4) An alkanediol

[JEE(Main)-2014]

Sol. (2)

Q.

[JEE(Main)-2014]

Sol. (3)

p-block – JEE Main Previous Year Questions with Solutions

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Q. Which one of the following reactions of Xenon compounds is not feasible ?

(1) $2 \mathrm{XeF}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{Xe}+4 \mathrm{HF}+\mathrm{O}_{2}$

(2) $\mathrm{XeF}_{6}+\mathrm{RbF} \rightarrow \mathrm{Rb}\left[\mathrm{XeF}_{7}\right]$

(3) $\mathrm{XeO}_{3}+6 \mathrm{HF} \rightarrow \mathrm{XeF}_{6}+3 \mathrm{H}_{2} \mathrm{O}$

(4) $3 \mathrm{XeF}_{4}+6 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{Xe}+\mathrm{XeO}_{3}+12 \mathrm{HF}+1.5 \mathrm{O}_{2}$

[aieee-2009]

Sol. (3)

Q. Which of the following statement is wrong ?

(1) Single N–N bond is weaker than the single P–P bond

(2) $\mathrm{N}_{2} \mathrm{O}_{4}$ has two resonance structures

(3) The stability of hydrides increases from NH3 to BiH3 in group 15 of the periodic table

(4) Nitrogen cannot form $\mathrm{d} \pi-\mathrm{p} \pi$ bond

[aieee-2011]

Sol. (3)

The stability of hydrides decreases from $\mathrm{NH}_{3}$ to $\mathrm{BiH}_{3}$ in group 15

Q. Which of the following statements regarding sulphur is incorrect ?

(1) At $600^{\circ} \mathrm{C}$ the gas mainly consists of $\mathrm{S}_{2}$ molceules

(2) The oxidation state of sulphur is never less than +4 in its compounds

(3) $\mathrm{S}_{2}$ molecule is paramagnetic

(4) The vapour at $200^{\circ} \mathrm{C}$ consists mostly of $\mathrm{S}_{8}$ rings

[aieee-2011]

Sol. (2)

Q. Boron cannot form which one of the following anions ?

(1) $\mathrm{B}(\mathrm{OH})_{4}^{-}$

(2) $\mathrm{BO}_{2}^{-}$

(3) $\mathrm{BF}_{6}^{3-}$

(4) $\mathrm{BH}_{4}^{-}$

[aieee-2011]

Sol. (3)

Due to the absence of vacant $2 \mathrm{d}-$ orbital, $\left[\mathrm{BF}_{6}\right]^{3-}$ is not form

Q. In view of the signs of $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}$ for the following reactions

$\mathrm{PbO}_{2}+\mathrm{Pb} \rightarrow 2 \mathrm{PbO}, \Delta_{\mathrm{r}} \mathrm{G}^{\circ}<0$

$\mathrm{SnO}_{2}+\mathrm{Sn} \rightarrow 2 \mathrm{SnO}, \Delta_{\mathrm{r}} \mathrm{G}^{\circ}>0$

Which oxidation states are more characteristic for lead and tin ?

(1) For lead + 4, for tin + 2

(2) For lead + 2, for tin + 2

(3) For lead + 4, for tin + 4

(4) For lead + 2, for tin + 4

[aieee-2011]

Sol. (4)

Q. The number of $\mathrm{S}-\mathrm{S}$ bonds in $\mathrm{SO}_{3}, \mathrm{S}_{2} \mathrm{O}_{3}^{2-}, \mathrm{S}_{2} \mathrm{O}_{6}^{2-}$ and $\mathrm{S}_{2} \mathrm{O}_{8}^{2-}$ respectively are :-

(1) 1, 0, 1, 0

(2) 0, 1, 1, 0

(3) 1, 0, 0, 1

(4) 0, 1, 0, 1

[JEE(Main)Online-2012]

Sol. (2)

Q. Which one of the following depletes ozone layer ?

(1) NO and freons

(2) $\mathrm{SO}_{2}$

(3) CO

( 4) $\mathrm{CO}_{2}$

[JEE(Main)Online-2012]

Sol. (1)

Q. In which of the following arrangements, the sequence is not strictly according to the property written against it ?

(1) $\mathrm{CO}_{2}<\mathrm{SiO}_{2}<\mathrm{SnO}_{2}<\mathrm{PbO}_{2}$ : increasing oxidisin g power

(2) B < C < O < N : increasing first ionisation enthalpy

(3) $\mathrm{NH}_{3}<\mathrm{PH}_{3}<\mathrm{AsH}_{3}<\mathrm{SbH}_{3}$ : increasing basic strength

(4) HF < HCl < HBr < HI : increasing acid strength

[JEE(Main)Online-2012]

Sol. (3)

Basic strength order : $\mathrm{NH}_{3}>\mathrm{PH}_{3}>\mathrm{AsH}_{3}>\mathrm{SbH}_{3}$

Q. The compound of Xenon with zero dipole moment is :-

(1) $\mathrm{XeO}_{3}$

(2) $\mathrm{XeO}_{2}$

(3) $\mathrm{XeF}_{4}$

(4) $\mathrm{XeOF}_{4}$

[JEE(Main)Online-2012]

Sol. (3)

Q. Which one of the following depletes ozone layer ?

(1) NO and freons

(2) $\mathrm{SO}_{2}$

(3) CO

(4) $\mathrm{CO}_{2}$

[JEE(Main)Online-2012]

Sol. (1)

Q. The formation of molecular complex $\mathrm{BF}_{3}-\mathrm{NH}_{3}$ results in a change in hybridisation of boron :-

(1) from $\operatorname{sp}^{3}$ to $\mathrm{sp}^{3} \mathrm{d}$

(2) from $\mathrm{sp}^{2}$ to $\mathrm{dsp}^{2}$

(3) from $\operatorname{sp}^{3}$ to $\mathrm{sp}^{2}$

(4) from $\mathrm{sp}^{2}$ to $\mathrm{sp}^{3}$

[JEE(Main)Online-2012]

Sol. (4)

Q. Trigonal bipyramidal geometry is shown by:

(1) $\mathrm{XeO}_{3} \mathrm{F}_{2}$

(2) $\mathrm{XeOF}_{2}$

(3) $\left[\mathrm{XeF}_{8}\right]^{2-}$

[JEE(Main)Online-2013]

Sol. (1)

Q. Oxidation state of sulphur in anions $\mathrm{SO}_{3,}^{2-} \mathrm{S}_{2} \mathrm{O}_{4}^{2-}$ and $\mathrm{S}_{2} \mathrm{O}_{6}^{2-}$ increases in the orders :

(1) $\mathrm{S}_{2} \mathrm{O}_{6}^{2-}<\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{SO}_{3}^{2-}$

(2) $\mathrm{SO}_{3}^{2-}<\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-} (3)$\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{SO}_{3}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-}$(4)$\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-}<\mathrm{SO}_{3}^{2-}$[JEE(Main)Online-2013] Sol. (3) Q.$\mathrm{XeO}_{4}$molecule is tetrahedral having: (1) Two p$\pi$– d$\pi$bonds (2) Four p$\pi$– d$\pi$bonds (3) One p$\pi$-d$\pi$bond (4) Three p$\pi$-d$\pi$bonds [JEE(Main)Online-2013] Sol. (2)$\rightarrow \mathrm{sp}^{3}$hybridisation$\rightarrow$No. of$(\mathrm{p} \pi-\mathrm{d} \pi)$bonds$=4$Q. The shape of \mathrm{IF}_{6}^{-} is : (1) Trigonally distorted octahedron (2) Pyramidal (3) Octahedral (4) Square antiprism [JEE(Main)Online-2013] Sol. (1) Trigonally distorted octahedron Q. Which has trigonal bipyramidal shape ? (1)$\mathrm{XeOF}_{4}$(2)$\mathrm{XeO}_{3}$(3)$\mathrm{XeO}_{3} \mathrm{F}_{2}$(4)$\mathrm{XeOF}_{2}$[JEE(Main)Online-2013] Sol. (3) Q. The catenation tendency of C, Si and Ge is in the order Ge < Si < C. The bond energies (in kJ$\mathrm{mol}^{-1}$) of C — C, Si —Si and Ge—Ge bonds are respectively : (1) 348, 260, 297 (2) 348, 297, 260 (3) 297, 348, 260 (4) 260, 297, 348 [JEE(Main)Online-2013] Sol. (2) Q. The gas evolved on heating$\mathrm{CaF}_{2}$and$\mathrm{SiO}_{2}$with concentrated$\mathrm{H}_{2} \mathrm{SO}_{4}$, on hydrolysis gives a white gelatinous precipitate. The precipitate is: (1) silica gel (2) silicic acid (3) hydrofluosilicic acid (4) calciumfluorosilicate [JEE(Main)Online-2014] Sol. (2) Q. Shapes of certain interhalogen compounds are stated below. Which one of them is not correctly stated? (1) IF_$_{7}:$Pentagonal bipyramid (2) BrF$_{5}:$Trigonal bipyramid (3) ICl_3: Planar dimeric (4)$\mathrm{BrF}_{3}:$Planar T-shaped [JEE(Main)Online-2014] Sol. (2) Q. Which of the following series correctly represents relations between the elements from X to Y? X  Y [JEE(Main)Online-2014] Sol. (3) Q. Which of the following statements about the depletion of ozone layer is correct? (1) The problem of ozone depletion is more serious at poles because ice crystals in the clouds over poles act as catalyst for photochemical reactions involving the decomposition of ozone by Cl• and ClO• radicals (2) The problem of ozone depletion is less serious at poles because$\mathrm{NO}_{2}$solidifies and is not available for consuming ClO• radicals (3) Oxides of nitrogen also do not react with ozone in stratosphere (4) Freons, chlorofluorocarbons, are inert chemically, they do not react with ozone in stratosphere [JEE(Main)Online-2014] Sol. (1) Q. Which of the following xenon-OXO compounds may not be obtained by hydrolysis of xenon fluorides ? (1)$\mathrm{XeO}_{2} \mathrm{F}_{2}$(2)$\mathrm{XeO}_{3}$(3)$\mathrm{XeO}_{4}$(4)$\mathrm{XeOF}_{4}$[JEE(Main)Online-2014] Sol. (3) Q. Hydrogen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases$\mathrm{H}_{2} \mathrm{O}_{2}$acts as a reducing agent in acid medium ? (1)$\mathrm{MnO}_{4}^{-}$(2)$\mathrm{SO}_{3}^{2-}$(3) KI (4)$\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$[JEE(Main)Online-2014] Sol. (1) Q. Consider the reaction$\mathrm{H}_{2} \mathrm{SO}_{3(\alpha q)}+\mathrm{Sn}_{(\alpha a)}^{4+}+\mathrm{H}_{2} \mathrm{O}_{(1)} \rightarrow \mathrm{Sn}_{(\mathrm{aq})}^{2+}+\mathrm{HSO}_{4(\mathrm{aq})}^{-}+3 \mathrm{H}_{(\mathrm{aq})}^{+}$Which of the following statements is correct? (1)$\mathrm{H}_{2} \mathrm{SO}_{3}$is the reducing agent because it undergoes oxidation (2)$\mathrm{H}_{2} \mathrm{SO}_{3}$is the reducing agent because it undergoes reduction (3)$\mathrm{Sn}^{4+}$is the reducing agent because it undergoes oxidation (4)$\mathrm{Sn}^{4+}$is the oxidizing agent because it undergoes oxidation [JEE(Main)Online-2014] Sol. (1) Q. The number and type of bonds in$\mathrm{C}_{2}^{2-}$ion in$\mathrm{CaC}_{2}$are : (1) Two$\sigma$bonds and one$\pi-$bond (2) Two$\sigma$bonds and two$\pi$– bonds (3) One$\sigma$bond and two$\pi$– bonds (4) One$\sigma$bond and one$\pi$– bond [JEE(Main)Online-2014] Sol. (3) Q. In the following sets of reactants which two sets best exhibit the amphoteric character of$\mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O} ?$Set-1$: \mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{XH}_{2} \mathrm{O}(\mathrm{s})$and$\mathrm{OH}^{-}(\mathrm{aq})$Set$-2: \mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{XH}_{2} \mathrm{O}(\mathrm{s})$and$\mathrm{H}_{2} \mathrm{O}(\ell)$Set-3$: \mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O}(\mathrm{s})$and$\mathrm{H}^{+}(\mathrm{aq})$Set-4:$\mathrm{Al}_{2} \mathrm{O}_{3} \cdot \mathrm{xH}_{2} \mathrm{O}(\mathrm{s})$and$\mathrm{NH}_{3}(\mathrm{aq})$(1) 1 and 2 (2) 2 and 4 (3) 1 and 3 (4) 3 and 4 [JEE(Main)Online-2014] Sol. (3) Q. Example of a three-dimensional silicate is : (1) Beryls (2) Zeolites (3) Feldspars (4) Ultramarines [JEE(Main)Online-2014] Sol. (1) Q. Which of the following compounds has a P-P bond :- (1)$\mathrm{H}_{4} \mathrm{P}_{2} \mathrm{O}_{5}$(2)$\left(\mathrm{HPO}_{3}\right)_{3}$(3)$\mathrm{H}_{4} \mathrm{P}_{2} \mathrm{O}_{7}$(4)$\mathrm{H}_{4} \mathrm{P}_{2} \mathrm{O}_{6}$[JEE(Main)Online-2015] Sol. (4) Q. Chlorine water on standing loses its colour and forms :- (1)$\mathrm{HCl}$and$\mathrm{HClO}_{2}$(2) HCl only (4) HCl and HOCl [JEE(Main)Online-2015] Sol. (4)$\mathrm{C} \ell_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{HCl}+\mathrm{HOCl}$Q. Which among the following is the most reactive ? (1)$\mathrm{I}_{2}$(2) Icl (3)$\mathrm{Cl}_{2}$( 4)$\mathrm{Br}_{2}$[JEE-Main2015] Sol. (2) Inter halogen compounds are more reactive than halogen except$\mathrm{F}_{2}$. Q. Which one has the highest boiling point ? (1) Kr (2) Xe (3) He (4) Ne [JEE-Main2015] Sol. (2) Boiling point order: He < Ne < Ar < Kr < Xe Q. From the following statements regarding$\mathrm{H}_{2} \mathrm{O}_{2}$, choose the incorrect statement : (1) It has to be stored in plastic or wax lined glass bottles in dark (2) It has to be kept away from dust (3) It can act only as an oxidizing agent (4) It decomposes on exposure to light [JEE-Main2015] Sol. (3)$\mathrm{H}_{2} \mathrm{O}_{2}$acts as aciding as well as reducing nature. Q. Which of the following are Lewis acids ? (1)$\mathrm{AlCl}_{3}$and$\mathrm{SiCl}_{4}$(2)$\mathrm{PH}_{3}$and$\mathrm{SiCl}_{4}$(3)$\mathrm{BCl}_{3}$and$\mathrm{AlCl}_{3}$(4)$\mathrm{PH}_{3}$and$\mathrm{BCl}_{3}$[JEE-Main2018] Sol. (3)$\mathrm{BCl}_{3} \& \mathrm{AlCl}_{3}$both have vacant p-orbital \& incomplete octet. So they act as Lewis acid. Q. The compound that does not produce nitrogen gas by the thermal decomposition is ( 1)$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$(2)$\mathrm{NH}_{4} \mathrm{NO}_{2}$(3)$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$(4)$\mathrm{Ba}\left(\mathrm{N}_{3}\right)_{2}$[JEE-Main2018] Sol. (3) Hydrogen – JEE Main Previous Year Questions with Solutions JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral. Simulator Previous Years AIEEE/JEE Mains Questions Q. Very pure hydrogen (99.9%) can be made by which of the following processes? (1) Reaction of salt like hydrides with water (2) Reaction of methane with steam (3) Mixing natural hydrocarbons of high molecular weight (4) Electrolysis of water [AIEEE 2012] Sol. (4) Very pure hydrogen (99.9%) can be made by electrolysis of water. Q. In which of the following reaction$\mathrm{H}_{2} \mathrm{O}_{2}$acts as a reducing agent ? (1) (1), (3) (2) (2), (4) (3) (1), (2) (4) (3), (4) [JEE(Main) 2014] Sol. (2) When$\mathrm{H}_{2} \mathrm{O}_{2}$act as reducing agent then it evolve. Q. Which of the following statements about$\mathrm{Na}_{2} \mathrm{O}_{2}$is not correct ? (1)$\mathrm{Na}_{2} \mathrm{O}_{2}$oxidises$\mathrm{Cr}^{3+}$to$\mathrm{CrO}_{4}^{2-}$in acid medium (2) It is diamagnetic in nature (3) It is the super oxide of sodium (4) It is a derivative of$\mathrm{H}_{2} \mathrm{O}_{2}$[JEE(Main) 2014] Sol. (3)$\mathrm{Na}_{2} \mathrm{O}_{2}$is peroxide of sodium Q. Hydrogen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases$\mathrm{H}_{2} \mathrm{O}_{2}$acts as a reducing agent in acid medium ? :- (1)$\mathrm{MnO}_{4}^{-}$(2)$\mathrm{SO}_{3}^{2-}$(3) KI (4)$\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$[JEE(Main)Online-2014] Sol. (1) Q. Permanent hardness in water cannot be cured by: (1) Treatment with washing soda (2) Calgon’s method (3) Boiling (4) Ion exchange method [JEE(Main)Online-2015] Sol. (3) Permanent hardness in water cannot cured by boiling of water Q. From the following statements regarding H2O2, choose the incorrect statement : (1) It has to be stored in plastic or wax lined glass bottles in dark (2) It has to be kept away from dust (3) It can act only as an oxidizing agent (4) It decomposes on exposure to light [JEE(Main)Online-2015] Sol. (3)$\mathrm{H}_{2} \mathrm{O}_{2}$can act as oxidizing as well as reducing agent depend on condition. Q. Hydrogen peroxide oxidises$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$to$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$in acidic medium but reduces$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$to$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$in alkaline medium. The other products formed are, respectively : [JEE(Main)Online-2018] (1)$\left(\mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\right)$and$\left(\mathrm{H}_{2} \mathrm{O}+\mathrm{OH}^{-}\right)$(2)$\mathrm{H}_{2} \mathrm{O}$and$\left(\mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\right)$(3)$\mathrm{H}_{2} \mathrm{O}$and$\left(\mathrm{H}_{2} \mathrm{O}+\mathrm{OH}^{-}\right)$(4)$\left(\mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\right)$and$\mathrm{H}_{2} \mathrm{O}$Sol. (2) Periodic Table – JEE Main Previous Year Questions with Solutions JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral. Simulator Previous Years AIEEE/JEE Mains Questions Q. The set representing the correct order of ionic radius is ? (1)$\mathrm{Li}^{+}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}$(2)$\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}>\mathrm{Li}^{+}>\mathrm{Na}^{+}$(3)$\mathrm{Li}^{+}>\mathrm{Be}^{2+}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+}$(4)$\mathrm{Na}^{+}>\mathrm{Li}^{+}>\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}$[AIEEE 2009] Sol. (4) Q. The correct order of electron gain enthalpy with negative sign of F, Cl, Br and I, having atomic number 9, 17, 35 and 53 respectively, is ? (1) I > Br > Cl > F (2) F > Cl > Br > I (3) Cl > F > Br > I (4) Br > Cl > I > F [AIEEE 2011] Sol. (3) Q. The increasing order of the ionic radii of the given isoelectronic species is ? (1)$\mathrm{K}^{+}, \mathrm{S}^{2-}, \mathrm{Ca}^{2+}, \mathrm{Cl}^{-}$(2)$\mathrm{Cl}^{-}, \mathrm{Ca}^{2+}, \mathrm{K}^{+}, \mathrm{S}^{2-}$(3)$\mathrm{S}^{2-}, \mathrm{Cl}^{-}, \mathrm{Ca}^{2+}, \mathrm{K}^{+}$(4)$\mathrm{Ca}^{2+}, \mathrm{K}^{+}, \mathrm{Cl}^{-}, \mathrm{S}^{2-}$[AIEEE 2012] Sol. (4) Q. Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ? (1) Ca < S < Ba < Se < Ar (2) S < Se < Ca < Ba < Ar (3) Ba < Ca < Se < S < Ar (4) Ca < Ba S < Se < Ar [JEE-Main 2013] Sol. (3) Q. The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of$\mathrm{Na}^{+}$will be? (1) – 2.55 eV (2) – 5.1 eV (3) – 10.2 eV (4) + 2.55 eV [JEE-Main 2013] Sol. (4) Q. Electron gain enthalpy with negative sign of fluorine is less than that of chlorine due to: (1) Smaller size of chlorine atom (2) Bigger size of 2p orbital of fluorine (3) High ionization enthalpy ol fluorine (4) Smaller size of fluorine atom [JEE-MAIN 2013 (OnLine)] Sol. (4) Q. The order of increasing sizes of atomic radii among the elements O, S, Se and As is ? (1) As < S < O < Se (2) O < S < As < Se (3) Se < S < As < O (4) O < S < Se < As [JEE-MAIN 2013 (OnLine)] Sol. (4) Q. Which is the correct order of second ionization potential of C, N, O and F in the following? (1) O > F > N > C (2) O > N > F > C (3) C > N > O > F (4) F > O > N > C [JEE-MAIN 2013 (OnLine)] Sol. (1) Q. Which of the following series correctly represents relations between the elements from X to Y ? [JEE-MAIN 2014 (OnLine)] Sol. (3) Q. Which of the following atoms has the highest first ionization energy ? (1) Sc (2) Rb (3) Na (4) K [JEE-MAIN 2016] Sol. (1) Due to poor shielding of d-electrons in Sc,$Z_{\mathrm{eff}}$of Sc becomes more so that ionisation energy of Sc is more than Na, K and Rb. Q. The group having isoelectronic species is :- (1)$\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}^{+}, \mathrm{Mg}^{2+}$(2)$\mathrm{O}^{-}, \mathrm{F}^{-}, \mathrm{Na}, \mathrm{Mg}^{+}$(3)$\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}, \mathrm{Mg}^{2+}$(4)$\mathrm{O}^{-}, \mathrm{F}^{-}, \mathrm{Na}^{+}, \mathrm{Mg}^{2+}$[JEE-MAIN 2017] Sol. (1) s-block – JEE Main Previous Year Questions with Solutions JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral. Simulator Previous Years AIEEE/JEE Mains Questions Q. The products obtained on heating$\mathrm{LiNO}_{3}$will be :- (1)$\mathrm{LiNO}_{2}+\mathrm{O}_{2}$(2)$\mathrm{Li}_{2} \mathrm{O}+\mathrm{NO}_{2}+\mathrm{O}_{2}$(3)$\mathrm{Li}_{3} \mathrm{N}+\mathrm{O}_{2}$(4)$\mathrm{Li}_{2} \mathrm{O}+\mathrm{NO}+\mathrm{O}_{2}$[AIEEE-2011] Sol. (2) Fact based. Q. What is the best description of the change that occurs when$\mathrm{Na}_{2} \mathrm{O}(\mathrm{s})$is dissolved in water ? (1) Oxidation number of sodium decreases (2) Oxide ion accepts sharing in a pair of electrons (3) Oxide ion donates a pair of electrons (4) Oxidation number of oxygen increases Sol. (3)$\mathrm{O}^{-2}+\mathrm{H}^{\ominus} \rightarrow \mathrm{O}-\mathrm{H}\left\{\mathrm{O}^{-2} \rightarrow \mathrm{H}^{\ominus}\right\}$Q. Which of the following on thermal-decomposition yields a basic as well as an acidic oxide ? (1)$\mathrm{NH}_{4} \mathrm{NO}_{3}$(2) NaNO$_{3}$(3)$\mathrm{KClO}_{3}$(4) CaCO$_{3}$[AIEEE-2012] Sol. (4) Q. Fire extinguishers contain$\mathrm{H}_{2} \mathrm{SO}_{4}$and which one of the following :- (1)$\mathrm{CaCO}_{3}$(2)$\mathrm{NaHCO}_{3}$and$\mathrm{Na}_{2} \mathrm{CO}_{3}$(3)$\mathrm{Na}_{2} \mathrm{CO}_{3}$(4)$\mathrm{NaHCO}_{3}$[JEE MAIN-2012, Online] Sol. (4) Solution not required Q. Based on lattice energy and other considerations, which one of the following alkali metal chloride is expected to have the highest melting point ? (1) RbCl (2) LiCl (3) KCl (4) NaCl [JEE MAIN-2012, Online] Sol. (4) NaCl having highest lattice energy have highest melting point among these. Q. Which one of the following will react most vigorously with water ? (1) Li (2) K (3) Rb (4) Na [JEE MAIN-2012, Online] Sol. (3) Down the group reactivity of s-block metals increases. Q. A metal M on heating in nitrogen gas gives Y. Y on treatment with$\mathrm{H}_{2} \mathrm{O}$gives a colourless gas which when passed through$\mathrm{CuSO}_{4}$solution gives a blue colour, Y is :- (1)$\mathrm{NH}_{3}$(2) MgO (3)$\mathrm{Mg}_{3} \mathrm{N}_{2}$(4)$\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$[JEE MAIN-2012, Online] Sol. (3)$\mathrm{M}+\mathrm{N}_{2} \rightarrow$metal nitride (y) so according to the given options answer is (3) Q. The correct statement for the molecule,$\mathrm{CSI}_{3}$, is : (1) it contains$\mathrm{Cs}^{3+}$and I– ions (2) it contains$\mathrm{Cs}^{+}$, I– and lattice I2 molecule (3) it is a covalent molecule (4) it contains$\mathrm{Cs}^{+}$and ions. [JEE(Main)-2014] Sol. (4)$\mathrm{CsI}_{3}$is ionic compound which have$\mathrm{Cs}^{\oplus}$and$\mathrm{I}_{3}^{\oplus}$ion. Q. Which of the following statements about$\mathrm{Na}_{2} \mathrm{O}_{2}$is not correct ? (1)$\mathrm{Na}_{2} \mathrm{O}_{2}$oxidises$\mathrm{Cr}^{3+}$to$\mathrm{CrO}_{4}^{2-}$in acid medium (2) It is diamagnetic in nature (3) It is the super oxide of sodium (4) It is a derivative of$\mathrm{H}_{2} \mathrm{O}_{2}$[JEE MAIN-2014, Online] Sol. (3)$\mathrm{Na}_{2} \mathrm{O}_{2}$is sodium peroxide not the superoxide. Q. Amongst LiCl, RbCl,$\mathrm{BeCl}_{2}$and$\mathrm{MgCl}_{2}$the compounds with the greatest and the least ionic character, respectively are : (1)$\mathrm{RbCl}$and$\mathrm{MgCl}_{2}$(2) LiCl and RbCl (3)$\mathrm{MgCl}_{2}$and$\mathrm{BeCl}_{2}$(4)$\mathrm{RbCl}$and$\mathrm{BeCl}_{2}$[JEE MAIN-2014, Online] Sol. (4) Due to smallest cationic size$\mathrm{BeCl}_{2}$is least ionic while due to biggest ionic size of$\mathrm{Rb}^{\oplus}$, RbCl has greatest ionic character. Q. The correct order of thermal stability of hydroxides is : [JEE(Main)Online-2015] Sol. (3) For the ionic compound having polyatomic anion, thermal stability increases down the group. Q. Which of the alkaline earth metal halide given below is essentially covalent in nature :- (1)$\mathrm{SrCl}_{2}$(2)$\mathrm{CaCl}_{2}$(3)$\mathrm{BeCl}_{2}$(4)$\mathrm{MgCl}_{2}$[JEE(Main)Online-2015] Sol. (3) Fact based. Chemical Bonding – JEE Main Previous Year Questions with Solutions JEE Main Previous Year Papers Questions of Chemistry With Solutions are available at eSaral. Simulator Previous Years AIEEE/JEE Mains Questions Q. The bond dissociation energy of B–F in$\mathrm{BF}_{3}$is 646 kJ$\mathrm{mol}^{-1}$whereas that of C–F in$\mathrm{CF}_{4}$is 515 kJ mol–1. The correct reason for higher B–F bond dissociation energy as compared to that of C–F is :- (1) Significant$\mathrm{p} \pi-\mathrm{p} \pi$interaction between B and F in$\mathrm{BF}_{3}$whereas there is not possibility of such interaction between C and F in$\mathrm{CF}_{4}$. (2) Lower degree of p – p interaction between B and F in$\mathrm{BF}_{3}$than that between C and F in$\mathrm{CF}_{4}$(3)Smaller size of B-atom as compared to that of C-atom (4) Stronger  bond between B and F in$\mathrm{BF}_{3}$as compared to that between C and F in$\mathrm{CF}_{4}$[AIEEE-2009] Sol. (1) Due to back bonding in BF3 molecule all B–F bond having partial double bond character. Q. Using MO theory predict which of the following species has the shortest bond length ? (1)$\mathrm{o}_{2}^{-}$(2)$\mathrm{O}_{2}^{2-}$(3)$\mathrm{O}_{2}^{2+}$(4)$\mathrm{O}_{2}^{+}$[AIEEE-2009] Sol. (3) Q. The hybridisation of orbitals of N atom in$\mathrm{NO}_{3}^{-}, \mathrm{NO}_{2}^{+}$and$\mathrm{NH}_{4}^{+}$are respectively:- [AIEEE-2011] Sol. (4) Q. The structure of$\mathrm{IF}_{7}$is :- (1) octahedral (2) pentagonal bipyramid (3) square pyramid (4) trigonal bipyramid [AIEEE-2011] Sol. (2) Q. Among the following the maximum covalent character is shown by the compound :- (1)$\mathrm{AlCl}_{3}$(2)$\mathrm{MgCl}_{2}$(3) FeCl$_{2}$(4)$\mathrm{SnCl}_{2}$[AIEEE-2011] Sol. (1)$\mathrm{Al}^{+3}$having highest polarizing power than other : having greater covalent character Q. Which of the following has maximum number of lone pairs associated with Xe (1)$\mathrm{XeO}_{3}$(2)$\mathrm{XeF}_{4}$(3) XeF$_{6}$(4)$\mathrm{XeF}_{2}$[AIEEE-2011] Sol. (4) Q. The number of types of bonds between two carbon atoms in calcium carbide is :- (1) One sigma, two pi (2) One sigma, one pi (3) Two sigma, one pi (4) Two sigma, two pi [AIEEE-2011] Sol. (1)$\mathrm{Ca}^{+2}(\mathrm{C} \equiv \mathrm{C})^{2-}$Q. The molecule having smallest bond angle is :- (1)$\mathrm{PCl}_{3}$(2)$\mathrm{NCl}_{3}$(4)$\mathrm{SbCl}_{3}$[AIEEE-2012] Sol. (4) Bond angle order$\mathrm{NCl}_{3}>\mathrm{PCl}_{3}>\mathrm{AsCl}_{3}>\mathrm{SbCl}_{3}$Q. In which of the following pairs the two species are not isostructural ? (1)$\mathrm{AIF}_{6}^{3-}$and$\mathrm{SF}_{6}$(3)$\mathrm{CO}_{3}^{2-}$and$\mathrm{NO}_{3}^{-}$(3)$\mathrm{PCl}_{4}^{+}$and$\mathrm{SiCl}_{4}$(4)$\mathrm{PF}_{5}$and$\mathrm{BrF}_{5}$[AIEEE-2012] Sol. (4) Q. The number of S–S bonds in$\mathrm{SO}_{3}, \mathrm{S}_{2} \mathrm{O}_{3}^{2-}, \mathrm{S}_{2} \mathrm{O}_{6}^{2-}$and$\mathrm{S}_{2} \mathrm{O}_{8}^{2-}$respectively are :- (1) 1, 0, 1, 0 (2) 0, 1, 1, 0 (3) 1, 0, 0, 1 (4) 0, 1, 0, 1 [JEE-MAINS(Online) 2012] Sol. (2) Q. Dipole moment is shown by :- (1) trans-2, 3-dichloro- 2-butene (2) 1, 2-dichlorobenzene (3) 1, 4-dichlorobenzene (4) trans-1, 2-dinitroethene [JEE-MAINS(Online) 2012] Sol. (2) Q. Among the following species which two have trigonal bipyramidal shape ? [JEE-MAINS(Online) 2012] Sol. (Bonus) Q. Among the following, the species having the smallest bond is :- (1) NO (2)$\mathrm{NO}^{+}$(3)$\mathrm{O}_{2}$(4)$\mathrm{NO}^{-}$[JEE-MAINS(Online) 2012] Sol. (2) Q. Based on lattice energy and other considerations, which one of the following alkali metal chloride is expected to have the highest melting point ? (1) RbCl (2) LiCl (3) KCl (4) NaCl [JEE-MAINS(Online) 2012] Sol. (4) Highest melting is of NaCl Q. Which of the following has the square planar structure :- (1)$\mathrm{NH}_{4}^{+}$(2)$\mathrm{CCl}_{4}$(3)$\mathrm{XeF}_{4}$(4)$\mathrm{BF}_{4}^{-}$[JEE-MAINS(Online) 2012] Sol. (3) Hybridisation$\mathrm{Sp}^{3} \mathrm{d}^{2}$Shape – square planar Q. The compound of Xenon with zero dipole moment is :- (1)$\mathrm{XeO}_{3}$(2)$\mathrm{XeO}_{2}$(3)$\mathrm{XeF}_{4}$(4)$\mathrm{XeOF}_{4}$[JEE-MAINS(Online) 2012] Sol. (3) Q. Among the following the molecule with the lowest dipole moment is :- (1)$\mathrm{CHCl}_{3}$(2)$\mathrm{CH}_{2} \mathrm{Cl}_{2}$(3)$\mathrm{CCl}_{4}$(4)$\mathrm{CH}_{3} \mathrm{Cl}$[JEE-MAINS(Online) 2012] Sol. (3)$\mathrm{CCl}_{4}<\mathrm{CHCl}_{3}<\mathrm{CH}_{2} \mathrm{Cl}_{2}<\mathrm{CH}_{3} \mathrm{Cl}(\text { Dipolar moment })$Q. The formation of molecular complex$\mathrm{BF}_{3}-\mathrm{NH}_{3}$results in a change in hybridisation of boron (1) from$\operatorname{sp}^{3}$to$\mathrm{sp}^{3} \mathrm{d}$(2) from$\operatorname{sp}^{2}$to$\mathrm{dsp}^{2}$(3) from$\operatorname{sp}^{3}$to$\mathrm{sp}^{2}$(4) from$\operatorname{sp}^{2}$to$\mathrm{sp}^{3}$[JEE-MAINS(Online) 2012] Sol. (4) Q. Among the following chloro-compound having the lowest dipole moment is :- (1)$\mathrm{CH}_{2} \mathrm{Cl}_{2}$(2)$\mathrm{CH}_{3} \mathrm{Cl}$(3) (4) Sol. (1)$\mathrm{CH}_{2} \mathrm{Cl}_{2}$has lowest dipole moment Q. Which one of the following molecules is expected to exhibit diamagnetic behaviour ? (1)$\mathrm{C}_{2}$(2)$\mathrm{N}_{2}$(3)$\mathrm{O}_{2}$(4)$\mathrm{S}_{2}$[AIEEE-2013] Sol. (2)$\mathrm{N}_{2}$is diamagnetic Q. Which of the following is the wrong statement? (1) ONCl and$\mathrm{ONO}^{-}$are not isoelectronic (2)$\mathrm{O}_{3}$molecule is bent (3) Ozone is violet-black in solid state (4) Ozone is diamagnetic gas [JEE-maIN 2013] Sol. (1) Number of electron in ONCl an$\mathrm{ONO}^{-}$is 32 & 24 respectively. Q. In which of the following pairs of molecules/ions, both the species are not likely to exist ? (1)$\mathrm{H}_{2}^{+}, \mathrm{He}_{2}^{2-}$(2)$\mathrm{H}_{2}^{-}, \mathrm{He}_{2}^{2-}$(3)$\mathrm{H}_{2}^{2+}, \mathrm{He}_{2}$(4)$\mathrm{H}_{2}^{-}, \mathrm{H} \mathrm{e}_{2}^{2+}$[JEE-main 2013] Sol. (3) Bond order of$\mathrm{H}_{2}^{2+} \& \mathrm{He}_{2}$is zero i.e. these molecule do not exist. Q. Stability of the species$\mathrm{Li}_{2}, \quad \mathrm{Li}_{2}^{-}$and$\mathrm{Li}_{2}^{+}$increases in the order of :- (1)$\mathrm{Li}_{2}<\mathrm{Li}_{2}^{+}<\mathrm{Li}_{2}^{-}$(2)$\mathrm{Li}_{2}^{-}<\mathrm{Li}_{2}^{+}<\mathrm{Li}_{2}$(3)$\mathrm{Li}_{2}<\mathrm{Li}_{2}<\mathrm{Li}_{2}^{+}$(4)$\mathrm{Li}_{2}^{-}<\mathrm{Li}_{2}<\mathrm{Li}_{2}^{+}$[JEE-main 2013] Sol. (2) Q. Trigonal bipyramidal geometry is shown by: (1)$\mathrm{XeO}_{3} \mathrm{F}_{2}$(2)$\mathrm{XeOF}_{2}$(3)$\left[\mathrm{XeF}_{8}\right]^{2-}$[JEE-MAINS(Online) 2013] Sol. (1) Q. In which of the following ionization processes the bond energy has increased and also the magnetic behaviour has changed from paramagnetic to diamagnetic ? (1)$\mathrm{NO} \rightarrow \mathrm{NO}^{+}$(2)$\mathrm{O}_{2} \rightarrow \mathrm{O}_{2}^{+}$(3)$\mathrm{N}_{2} \rightarrow \mathrm{N}_{2}^{+}$( 4)$\mathrm{C}_{2} \rightarrow \mathrm{C}_{2}^{+}$[JEE-MAINS(Online) 2013] Sol. (1) Q. Which one of the following molecules is polar? (1)$\mathrm{CF}_{4}$(2)$\mathrm{SbF}_{5}$(3)$\mathrm{IF}_{5}$(4)$\mathrm{XeF}_{4}$[JEE-MAINS(Online) 2013] Sol. (3) Q. Oxidation state of sulphur in anions$\mathrm{SO}_{3,}^{2-} \mathrm{S}_{2} \mathrm{O}_{4}^{2-}$and$\mathrm{S}_{2} \mathrm{O}_{6}^{2-}$increases in the orders : (1)$\mathrm{S}_{2} \mathrm{O}_{6}^{2-}<\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{SO}_{3}^{2-}$(2)$\mathrm{SO}_{3}^{2-}<\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-}$(3)$\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{SO}_{3}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-}$(4)$\mathrm{S}_{2} \mathrm{O}_{4}^{2-}<\mathrm{S}_{2} \mathrm{O}_{6}^{2-}<\mathrm{SO}_{3}^{2-}$[JEE-MAINS(Online) 2013] Sol. (3) Q. Bond order normally gives idea of stability of a molecular species. All the molecules viz.$\mathrm{H}_{2}, \mathrm{Li}_{2}$and$\mathrm{B}_{2}$have the same bond order yet they are not equally stable. Their stability order is: (1)$\mathrm{Li}_{2}>\mathrm{H}_{2}>\mathrm{B}_{2}$(2)$\mathrm{H}_{2}>\mathrm{B}_{2}>\mathrm{Li}_{2}$(3)$\mathrm{B}_{2}>\mathrm{H}_{2}>\mathrm{Li}_{2}$(4)$\mathrm{Li}_{2}>\mathrm{B}_{2}>\mathrm{H}_{2}$[JEE-MAINS(Online) 2013] Sol. (2) Q. The solubility order for alkali metal fluoride in water is : (1)$\mathrm{LiF}<\mathrm{NaF}<\mathrm{KF}<\mathrm{RbF}$(2)$\mathrm{LiF}>\mathrm{NaF}>\mathrm{KF}>\mathrm{RbF}$(3)$\mathrm{RbF}<\mathrm{KF}<\mathrm{NaF}<\mathrm{LiF}$(4)$\mathrm{LiF}<\mathrm{RbF}<\mathrm{KF}<\mathrm{NaF}$[JEE-MAINS(Online) 2013] Sol. (1) Solubility order LiF < NaF < KF < RbF Q.$\mathrm{XeO}_{4}$molecule is tetrahedral having : (1) Two p$\pi$-d$\pi$bonds (2) Four p$\pi$– d$\pi$bonds (3) One$\mathrm{p} \pi-\mathrm{d} \pi$bond (4) Three p$\pi$-d$\pi$bonds [JEE-MAINS(Online) 2013] Sol. (2) Q. Bond distance in HF is 9.17 ×$10^{-11}$m. Dipole moment of HF is 6.104 × 10–30 Cm. The percent ionic character in HF will be : (electron charge = 1.60 ×$10^{-19}$C) (1) 61.0% (2) 38.0% (3) 35.5% (4) 41.5% [JEE-MAINS(Online) 2013] Sol. (4) Q. The shape of$\mathrm{IF}_{6}^{-}$is : (1) Trigonally distorted octahedron (2) Pyramidal (3) Octahedral (4) Square antiprism [JEE-MAINS(Online) 2013] Sol. (1) Q. Which has trigonal bipyramidal shape ? (1)$\mathrm{XeOF}_{4}$(2)$\mathrm{XeO}_{3}$(3)$\mathrm{XeO}_{3} \mathrm{F}_{2}$(4)$\mathrm{XeOF}_{2}$[JEE-MAINS(Online) 2013] Sol. (3) Q. The catenation tendency of C, Si and Ge is in the order Ge < Si < C. The bond energies (in kJ$\mathrm{mol}^{-1}$) of C — C, Si —Si and Ge—Ge bonds are respectively : (1) 348, 260, 297 (2) 348, 297, 260 (3) 297, 348, 260 (4) 260, 297, 348 [JEE-MAINS(Online) 2013] Sol. (2) Catenation/Bond energy order C – C > Si – Si > Ge – Ge Q. In which of the following sets, all the given species are isostructural ? (1)$\mathrm{BF}_{3}, \mathrm{NF}_{3}, \mathrm{PF}_{3}, \mathrm{AlF}_{3}$(2)$\mathrm{PCl}_{3}, \mathrm{AlCl}_{3}, \mathrm{BCl}_{3}, \mathrm{SbCl}_{3}$(3)$\mathrm{BF}_{4}^{-}, \mathrm{CCl}_{4}, \mathrm{NH}_{4}^{+}, \mathrm{PCl}_{4}^{+}$(4)$\mathrm{CO}_{2}, \mathrm{NO}_{2}, \mathrm{ClO}_{2}, \mathrm{SiO}_{2}$[JEE-MAINS(Online) 2013] Sol. (3)$\mathrm{BF}_{4}^{-}, \mathrm{CC}_{4}, \mathrm{NH}_{4}^{+}, \mathrm{PCl}_{4}^{+}$are terahedral Q. The internuclear distances in O —O bonds for O,$\mathrm{O}_{2}, \mathrm{O}^{-}$2 and O respectively are : (1) 1.49 Å, 1.21 Å, 1.12 Å, 1.30 Å (2) 1.30 Å, 1.49 Å, 1.12 Å, 1.21 (3) 1.12 Å, 1.21 Å, 1.30 Å, 1.49 Å (4) 1.21 Å, 1.12 Å, 1.49 Å, 1.30 Å [JEE-MAINS(Online) 2013] Sol. (3) Q. Which one of the following properties is not shown by NO ? (1) It combines with oxygen to form nitrogen dioxide (2) It’s bond order is 2.5 (3) It is diamagnetic in gaseous state (4) It is a neutral oxide [JEE-main 2014] Sol. (3) Q. For which of the following molecule significant$\mu \neq 0$[JEE-main 2014] Sol. (2) Q. The number and type of bonds in$\mathrm{C}_{2}^{2-} \mathrm{ion}$in$\mathrm{CaC}_{2}$are: (1) Two$\sigma$bonds and one$\pi-$bond (2) Two$\sigma$bonds and two$\pi-$bonds (3) One$\sigma$bond and two$\pi-$bonds (4) One$\sigma$bond and one$\pi-$bond [JEE-MAINS(Online) 2014] Sol. (3) Q. For the compounds$\mathrm{CH}_{3} \mathrm{Cl}, \mathrm{CH}_{3} \mathrm{Br}, \mathrm{CH}_{3} \mathrm{I}$and$\mathrm{CH}_{3} \mathrm{F}$(1)$\mathrm{CH}_{3} \mathrm{F}<\mathrm{CH}_{3} \mathrm{Br}<\mathrm{CH}_{3} \mathrm{Cl}<\mathrm{CH}_{3} \mathrm{I}$(2)$\mathrm{CH}_{3} \mathrm{F}<\mathrm{CH}_{3} \mathrm{Cl}<\mathrm{CH}_{3} \mathrm{Br}<\mathrm{CH}_{3} \mathrm{I}$(3)$\mathrm{CH}_{3} \mathrm{Cl}<\mathrm{CH}_{3} \mathrm{Br}<\mathrm{CH}_{3} \mathrm{F}<\mathrm{CH}_{3} \mathrm{I}$, the correct order of increasing C-halogen bond length is : (4)$\mathrm{CH}_{3} \mathrm{F}<\mathrm{CH}_{3} \mathrm{I}<\mathrm{CH}_{3} \mathrm{Br}<\mathrm{CH}_{3} \mathrm{Cl}$[JEE-MAINS(Online) 2014] Sol. (2) Q. Which of the following has unpaired electron(s) ? (1)$\mathrm{O}_{2}^{-}$(2)$\mathrm{N}_{2}^{2+}$(3)$\mathrm{O}_{2}^{2-}$(4)$\mathrm{N}_{2}$[JEE-MAINS(Online) 2014] Sol. (1)$\mathrm{O}_{2}^{-}$ha one unpaired electron Q. In allene$\left(\mathrm{C}_{3} \mathrm{H}_{4}\right)$, the type(s) of hybridization of the carbon atoms is (are): (1) only sp$^{2}$(2)$\mathrm{sp}^{2}$and$\mathrm{sp}$(3) sp and sp$^{3}$(4)$\mathrm{sp}^{2}$and$\mathrm{sp}^{3}$[JEE-MAINS(Online) 2014] Sol. (2) Q. Shapes of certain interhalogen compounds are stated below. Which one of them is not correctly stated? (1) IF$_{7}:$Pentagonal bipyramid (2) BrF$_{5}:$Trigonal bipyramid (4)$\mathrm{BrF}_{3}:$Planar T-shaped [JEE-MAINS(Online) 2014] Sol. (2)$\mathrm{BrF}_{5}$have square pyramidal shape. Q. The correct order of bond dissociation energy among$\mathrm{N}_{2}, \mathrm{O}_{2}, \mathrm{o}_{2}^{-}$is shown in which of the following arrangements? (1)$\mathrm{N}_{2}>\mathrm{O}_{2}>\mathrm{O}_{2}^{-}$(2)$\mathrm{O}_{2}>\mathrm{O}_{2}^{-}>\mathrm{N}_{2}$(3)$\mathrm{N}_{2}>\mathrm{O}_{2}^{-}>\mathrm{O}_{2}$(4)$\mathrm{O}_{2}^{-}>\mathrm{O}_{2}>\mathrm{N}_{2}$[JEE-MAINS(Online) 2014] Sol. (1) Q. Which of the following molecules has two sigma$(\sigma)$and two$\operatorname{pi}(\pi)$bonds :- (1) HCN (2)$\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{Cl}_{2}$(3)$\mathrm{N}_{2} \mathrm{F}_{2}$(4)$\mathrm{C}_{2} \mathrm{H}_{4}$[JEE-MAINS(Online) 2014] Sol. (1) Q. Which one of the following molecules is paramagnetic? (1) NO ( 2)$\mathrm{O}_{3}$(3)$\mathrm{N}_{2}$(4) CO [JEE-MAINS(Online) 2014] Sol. (1) NO has unpaired e$^{-} \therefore$paramagnetic is nature Q. Amongst LiCl, RbCl,$\mathrm{BeCl}_{2}$and$\mathrm{MgCl}_{2}$the compounds with the greatest and the least ionic character, respectively are : (1)$\mathrm{RbCl}$and$\mathrm{MgCl}_{2}$(2) LiCl and RbCl (3)$\mathrm{MgCl}_{2}$and$\mathrm{BeCl}_{2}$(4)$\mathrm{RbCl}$and$\mathrm{BeCl}_{2}$[JEE-MAINS(Online) 2014] Sol. (4) RbCl has highest ionic & and$\mathrm{BeCl}_{2}$is most covalent Q. The species in which the N atom is in a state of sp hybridization is :- (1)$\mathrm{NO}_{2}$(2)$\mathrm{NO}_{2}^{+}$(3)$\mathrm{NO}_{2}^{-}$(4)$\mathrm{NO}_{3}^{-}$[JEE-MAINS 2016] Sol. (2) Q. Which of the following species is not paramagnetic :- (1)NO (2) CO (3)$\mathrm{O}_{2}$(4)$\mathrm{B}_{2}$[JEE-MAINS 2017] Sol. (2) Q. Total number of lone pair of electrons in$\mathrm{I}_{3}^{-} \mathrm{ion}$is (1) 6 (2) 9 (3) 12 (4) 3 [JEE-MAINS 2018] Sol. (2) Q. According to molecular orbital theory, which of the following will not be a viable molecule ? (1)$\mathrm{He}_{2}^{+}$(2)$\mathrm{H}_{2}^{-}$(3)$\mathrm{H}_{2}^{2-}$(4)$\mathrm{He}_{2}^{2+}$[JEE-MAINS 2018] Sol. (3) Q. Which of the following compounds contain(s) no covalent bond(s) ?$\mathrm{KCl}, \mathrm{PH}_{3}, \mathrm{O}_{2}, \mathrm{B}_{2} \mathrm{H}_{6}, \mathrm{H}_{2} \mathrm{SO}_{4}(1) \mathrm{KCl}, \mathrm{H}_{2} \mathrm{SO}_{4}$(2) KC1 (3)$\mathrm{KCl}, \mathrm{B}_{2} \mathrm{H}_{6}$(4)$\mathrm{KCl}, \mathrm{B}_{2} \mathrm{H}_{6}, \mathrm{PH}_{3}\$

[JEE-MAINS 2018]

Sol. (2)