A metal surface is exposed to
Question: A metal surface is exposed to $500 \mathrm{~nm}$ radiation. The threshold frequency of the metal for photoelectric current is $4.3 \times 10^{14} \mathrm{~Hz}$. The velocity of ejected electron is $\times 10^{5} \mathrm{~ms}^{-1}$ (Nearest integer) $\left[\right.$ Use $\left.: \mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}, \mathrm{m}_{\mathrm{e}}=9.0 \times 10^{-31} \mathrm{~kg}\right]$ Solution: $v:$ speed of electron having max. K.E. $\Rightarrow$ from Einstein equation : $E=\phi+K \cd...
Read More →For water
Question: For water $\Delta_{\text {vap }} \mathrm{H}=41 \mathrm{~kJ} \mathrm{~mol}^{-1}$ at $373 \mathrm{~K}$ and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is $\mathrm{kJ} \mathrm{mol}^{-1}$ $\left[\right.$ Use $\left.: \mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right]$ Solution: Given equation is $\mathrm{H}_{2} \mathrm{O}(\ell) \longrightarrow \math...
Read More →Sulphurous acid H2SO3
Question: Sulphurous acid $\left(\mathrm{H}_{2} \mathrm{SO}_{3}\right)$ has $\mathrm{Ka}_{1}=1.7 \times 10^{-2}$ and $\mathrm{Ka}_{2}=6.4 \times 10^{-8}$. The $\mathrm{pH}$ of $0.588 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{3}$ is_____________ . (Round off to the Nearest Integer) Solution: $\mathrm{H}_{2} \mathrm{SO}_{3}$ [Dibasic acid] $\mathrm{c}=0.588 \mathrm{M}$ $\Rightarrow \quad \mathrm{pH}$ of solution $\mathrm{p}$ due to First dissociation only since $\mathrm{K}_{\mathrm{a}},\mathrm{Ka}_{2...
Read More →The equilibrium constant
Question: The equilibrium constant $K_{c}$ at $298 K$ for the reaction $\mathrm{A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D}$ is 100 . Starting with an equimolar solution with concentrations of $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ all equal to $1 \mathrm{M}$, the equilibrium concentration of $\mathrm{D}$ is $\times 10^{-2}$ M. (Nearest integer) Solution: $\mathrm{A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D}: \mathrm{K}_{\mathrm{eq}}=100$ $1 \mathrm{M} \quad 1...
Read More →Given below are two statements :
Question: Given below are two statements : Statement I : The nucleophilic addition of sodium hydrogen sulphite to an aldehyde or a ketone involves proton transfer to form a stable ion. Statement II : The nucleophilic addition of hydrogen cyanide to an aldehyde or a ketone yields amine as final product. In the light of the above statements, choose the most appropriate answer from the options given below:Both Statement I and Statement II are true.Statement I is true but Statement II is false.State...
Read More →In the sulphur estimation
Question: In the sulphur estimation, $0.471 \mathrm{~g}$ of an organic compound gave $1.44 \mathrm{~g}$ of barium sulphate. The percentage of sulphur in the compound is ____________. $\%$ (Nearest integer) (Atomic Mass of $\mathrm{Ba}=137 \mathrm{u}$ ) Solution: Molecular mass of $\mathrm{BaSO}_{4}=233 \mathrm{~g}$. $\because 233 \mathrm{BaSO}_{4}$ contain $\rightarrow 32 \mathrm{~g}$ sulphur \therefore 1.44 \mathrm{~g} \mathrm{BaSO}_{4} \text { contain } \rightarrow \frac{32}{233} \times 1.44 \...
Read More →At 363 K, the vapour pressure of A is 21 kPa and that of B is 18 kPa.
Question: At $363 \mathrm{~K}$, the vapour pressure of $\mathrm{A}$ is $21 \mathrm{kPa}$ and that of $\mathrm{B}$ is $18 \mathrm{kPa}$. One mole of $\mathrm{A}$ and 2 moles of B are mixed. Assuming that this solution is ideal, the vapour pressure of the mixture is__________ $\mathrm{kPa}$. (Round of to the Nearest Integer). Solution: Given $\mathrm{P}_{\mathrm{A}}^{0}=21 \mathrm{kPa} \quad \Rightarrow \mathrm{P}_{\mathrm{B}}^{0}=18 \mathrm{kPa}$ $\rightarrow$ An Ideal solution is prepared by mix...
Read More →In the following sequence of reactions,
Question: In the following sequence of reactions, $\mathrm{C}_{3} \mathrm{H}_{6} \stackrel{\mathrm{H}^{+} / \mathrm{H}_{2} \mathrm{O}}{\longrightarrow} \mathbf{A} \stackrel{\mathrm{KIO}}{\text { dil KOH }} \longrightarrow \mathbf{B}+\mathbf{C}$ The compounds $\mathbf{B}$ and $\mathbf{C}$ respectively are : $\mathrm{Cl}_{3} \mathrm{COOK}, \mathrm{HCOOH}$$\mathrm{CI}_{3} \mathrm{COOK}, \mathrm{CH}_{3} \mathrm{I}$$\mathrm{CH}_{3} \mathrm{I}, \mathrm{HCOOK}$$\mathrm{CHI}_{3}, \mathrm{CH}_{3} \mathrm...
Read More →Show the following question
Question: Consider the given reaction, the product $\mathbf{A}$ is :Correct Option: , 3 Solution:...
Read More →The number of orbitals
Question: with $\mathrm{n}=5, \mathrm{~m}_{1}=+2$ is__________ . (Round off to the Nearest Integer). Solution: For, $\mathrm{n}=5$ $\ell=(0,1,2,3,4)$ If $\ell=0, \mathrm{~m}=0$ $\ell=1, \mathrm{~m}=\{-1,0,+1\}$ $\ell=2, \mathrm{~m}=\{-2,-1,0,+1,+2\}$ $\ell=3, \mathrm{~m}=\{-3,-2,-1,0,+1,+2,+3\}$ $\ell=4, \mathrm{~m}=\{-4,-3,-2,-1,0,+1,+2,+3,+4\}$ $5 \mathrm{~d}, 5 \mathrm{f}$ and $5 \mathrm{~g}$ subshell contain one-one orbital having $\mathrm{m}_{\ell}=+2$...
Read More →Hydrogen peroxide reacts with iodine in basic medium to give:
Question: Hydrogen peroxide reacts with iodine in basic medium to give:$\mathrm{IO}_{4}^{-}$$\mathrm{IO}^{-}$$\mathrm{I}^{-}$$\mathrm{IO}_{3}^{-}$Correct Option: , 3 Solution: $\mathrm{I}_{2}+\mathrm{H}_{2} \mathrm{O}_{2}+2 \mathrm{OH} \longrightarrow 2 \mathrm{I}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}$...
Read More →Solve the following equations
Question: Consider the given reaction, Identify ' $\mathbf{X}^{\prime}$ and ' $\mathbf{Y}^{\prime}$ :Correct Option: , 3 Solution:...
Read More →The stereoisomers that are formed by electrophilic addition of bromine to trans-but-2-ene is/are :
Question: The stereoisomers that are formed by electrophilic addition of bromine to trans-but-2-ene is/are :2 enantiomers and 2 mesomers2 identical mesomers2 enantiomers1 racemic and 2 enantiomersCorrect Option: , 2 Solution:...
Read More →The number of stereoisomers
Question: The number of stereoisomers possible for $1,2-$ dimethyl cyclopropane is :OneFourTwoThreeCorrect Option: , 4 Solution:...
Read More →Which one of the following compounds is not aromatic ?
Question: Which one of the following compounds is not aromatic ?Correct Option: , 3 Solution:...
Read More →Prove the following
Question: Consider the above reaction where $6.1 \mathrm{~g}$ of benzoic acid is used to get $7.8 \mathrm{~g}$ of m-bromo benzoic acid. The percentage yield of the product is_________. (Round off to the Nearest integer) [Given : Atomic masses : $\mathrm{C}=12.0 \mathrm{u}, \mathrm{H}: 1.0 \mathrm{u}$, $\mathrm{O}: 16.0 \mathrm{u}, \mathrm{Br}=80.0 \mathrm{u}]$ Solution: Moles of Benzoic acid $=\frac{6.1}{122}$ $=$ moles of m-bromobenzoic acid So, weight of m-bromobenzoic acid $=\frac{6.1}{122} \...
Read More →Chalcogen group elements are :
Question: Chalcogen group elements are :Se, Tb and Pu.Se, Te and Po.$\mathrm{S}, \mathrm{Te}$ and $\mathrm{Pm}$.$\mathrm{O}, \mathrm{Ti}$ and Po.Correct Option: , 2 Solution: Group 16/oxygen family is known as Chalcogens the members are $\mathrm{O}, \mathrm{S}, \mathrm{Se}, \mathrm{Te}$, Po...
Read More →10.0 ml Na2CO3 solution is titrated aginst 0.2 M HCL solution.
Question: $10.0 \mathrm{ml}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ solution is titrated against $0.2$ $\mathrm{M} \mathrm{HCl}$ solution. The following titre values were obtained in 5 readings. $4.8 \mathrm{ml}, 4.9 \mathrm{ml}, 5.0 \mathrm{ml}, 5.0 \mathrm{ml}$ and $5.0 \mathrm{ml}$ Based on these readings, and convention of titrimetric estimation of concentration of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ solution is_______ $\mathrm{mM}$. (Round off to the Nearest integer) Solution: Most precise volu...
Read More →Solve this
Question: The class of drug to which chlordiazepoxide with above structure belongs is :AntacidAnalgesicTranquilizerAntibioticCorrect Option: , 3 Solution: The drug named chlordiate poxide is example of tranquilizer....
Read More →Which one of the following compounds is aromatic in nature?
Question: Which one of the following compounds is aromatic in nature? Correct Option: , 4 Solution: (1) (Acenaphthene)...
Read More →In Duma's method of estimation of nitrogen,
Question: In Duma's method of estimation of nitrogen, $0.1840 \mathrm{~g}$ of an organic compound gave $30 \mathrm{~mL}$ of nitrogen collected at $287 \mathrm{~K}$ and $758 \mathrm{~mm}$ of Hg pressure. The percentage composition of nitrogen in the compound is___________ (Round off to the Nearest Integer). Solution: In Duma's method of estimation of Nitrogen. $0.1840 \mathrm{gm}$ of organic compound gave $30 \mathrm{~mL}$ of nitrogen which is collected at $287 \mathrm{~K} \ 758$ $\mathrm{mm}$ of...
Read More →Arrange the following Cobalt
Question: Arrange the following Cobalt complexes in the order of increasing Crystal Field Stabilization Energy (CFSE) value. Complexes : $\left[\underset{\mathrm{A}}{\mathrm{CoF}_{6}}\right]^{3-},\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+},\left[\underset{\mathrm{B}}{\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}}\right]^{3+}$ and $\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}$ Choose the correct option :$\mathrm{A}\mathrm{B}\mathrm{C}\mathrm{D}$$BACD$$\mathrm{B}\mathrm...
Read More →A solute a dimerizes in water.
Question: A solute a dimerizes in water. The boiling point of a 2 molar solution of $\mathrm{A}$ is $100.52^{\circ} \mathrm{C}$. The percentage association of $A$ is_______. (Round off to the Nearest integer) [Use: $\mathrm{K}_{\mathrm{b}}$ for water $=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ Boiling point of water $=100^{\circ} \mathrm{C}$ ] Solution: $\Delta \mathrm{T}_{\mathrm{b}}=\mathrm{T}_{\mathrm{b}}-\mathrm{T}_{\mathrm{b}}{ }^{0}$ $100.52-100$ $=0.52^{\circ} \mathrm{C}$ $i=\left...
Read More →The solution of CdSO4, in water is
Question: The solubility of $\mathrm{CdSO}_{4}$ in water is $8.0 \times 10^{-4} \mathrm{~mol} \mathrm{~L}^{-1}$. Its solubility in $0.01 \mathrm{M}$ $\mathrm{H}_{2} \mathrm{SO}_{4}$ solution is_________ $\times 10^{-6} \mathrm{~mol} \mathrm{~L}^{-1}$. (Round off to the Nearest integer) (Assume that solubility is much less than $0.01 \mathrm{M}$ ) Solution: In pure water, $\mathrm{K}_{\mathrm{sp}}=\mathrm{S}^{2}=\left(8 \times 10^{-4}\right)^{2}$ $=64 \times 10^{-8}$ In $0.01 \mathrm{M} \mathrm{H...
Read More →Given below are two statements :
Question: Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Heavy water is used for the study of reaction mechanism. Reason (R) : The rate of reaction for the cleavage of $\mathrm{O}-\mathrm{H}$ bond is slower than that of $\mathrm{O}-\mathrm{D}$ bond. Choose the most appropriate answer from the options given below :Both (A) and (R) are true but (R) is not the true explanation of (A).Both $\mathbf{( A )}$ and $\mathbf{( R )...
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