What is the importance of heavy water?
Question: What is the importance of heavy water? Solution: Heavy water is water that contains heavy hydrogen D2O. It is used as a moderator in nuclear reactors and exchange reactions for the study of reaction mechanisms....
Read More →The basic principle of a hydrogen economy is transportation
Question: The basic principle of a hydrogen economy is transportation and storage of energy in the form of liquid or gaseous hydrogen. Which property of hydrogen may be useful for this purpose? Support your answer with the chemical equation if required. Solution: Being a liquid, less consumption of volume takes place, so transportation can be done easily. Thus, the basic property of hydrogen which is useful for hydrogen economy is that it can be converted into a liquid by cooling under high pres...
Read More →Find the equation of a line passing through the origin and making an angle
Question: Find the equation of a line passing through the origin and making an angle of $120^{\circ}$ with the positive direction of the $x$-axis. Solution: As angle is given so we have to find slope first give by m = tan $\mathrm{m}=\tan 120^{\circ}$ $\mathrm{m}=\tan \left(180^{\circ}-60^{\circ}\right) \Rightarrow-\tan 60^{\circ}=-(\sqrt{3})$ ( $\tan \left(180^{\circ}-\theta\right)$ is in II quadrant, $\tan x$ is negative) Now equation of line passing through origin is given as y = mx $y=-(\sqr...
Read More →Why is the Ionisation enthalpy of hydrogen
Question: Why is the Ionisation enthalpy of hydrogen higher than that of sodium? Solution: To remove a valence electron from the H atom is more difficult than Na atom due to higher nuclear attraction so more energy would be required. Thus, ionisation enthalpy of hydrogen is higher than sodium....
Read More →Hydrogen generally forms covalent
Question: Hydrogen generally forms covalent compounds. Give reason. Solution: Hydrogen can lose or gain an electron to attain noble gas configuration as it has only one electron in its outermost shell. The ionization enthalpy of hydrogen is high and their electron gain enthalpy is slightly negative. So they generally form covalent compounds....
Read More →Give reasons why hydrogen
Question: Give reasons why hydrogen resembles alkali metals? Solution: Hydrogen is an analogous element as its properties are shared with alkali and halogens in its electronic configuration. The electronic configuration of hydrogen (1s1) is similar to that of alkali metals (ns1) which shows that only one electron is present in their valence shell. So if they lose that single electron, a uni-positive ion would be formed....
Read More →Find the equation of a line whose inclination with the x - axis is
Question: Find the equation of a line whose inclination with the $x$-axis is $150^{\circ}$ and which passes through the point $(3,-5)$. Solution: As angle is given so we have to find slope first give by m = tan $m=\tan 150^{\circ}$ $\mathrm{m}=\tan \left(180^{\circ}-30^{\circ}\right) \Rightarrow-\tan 30^{\circ}=-\frac{1}{\sqrt{3}}\left(\tan \left(180^{\circ}-\theta\right)\right.$ is in II quadrant, $\tan x$ is negative) Now the line is passing through the point $(3,-5)$. Using the slope - interc...
Read More →Rohan heard that instructions were given to the laboratory
Question: Rohan heard that instructions were given to the laboratory attendant to store a particular chemical i.e., keep it in the darkroom, add some urea in it, and keep it away from dust. This chemical acts as an oxidising as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents (i) Write the name of this compound. (ii) Explain why such precautions are taken for storing this chemica...
Read More →The line y=m x+1 is a tangent to the curve
Question: The line $y=m x+1$ is a tangent to the curve $y^{2}=4 x$, if the value of $m$ is A. 1 B. 2 C. 3 D. $\frac{1}{2}$ Solution: It is given that the line $y=m x+1$ is a tangent to the curve $y^{2}=4 x$. Slope of the line $=\mathrm{m}$ Slope of the curve $\frac{d y}{d x}$, Differentiating the curve we get $2 y \frac{d y}{d x}=4$ $\Rightarrow \frac{d y}{d x}=\frac{2}{y}$ $\Rightarrow \frac{2}{y}=m$ $\Rightarrow y=\frac{2}{m}$ $\because$ The given line is a tangent to the curve so the point pa...
Read More →When the first element of the periodic
Question: When the first element of the periodic table is treated with dioxygen, it gives a compound whose solid-state floats on its liquid state. This compound can act as an acid as well as a base. What products will be formed when this compound undergoes authorisation? Solution: Hydrogen is the first element and when it reacts with dioxygen it forms water. Water has an amphoteric nature that acts as both acid and base. The solid-state of water is ice. It floats on water due to its lower densit...
Read More →Explain why HCl is a gas and HF is a liquid.
Question: Explain why HCl is a gas and HF is a liquid. Solution: Due to the formation of strong and stable hydrogen bonding, high energy is required to break the H-F bond. So the boiling point of HF is more than HCl and due to which HF is a liquid and HCl is a gas....
Read More →Dihydrogen reacts with dioxygen (O2) to form water.
Question: Dihydrogen reacts with dioxygen (O2) to form water. Write the name and formula of the product when the isotope of hydrogen which has one proton and one neutron in its nucleus is treated with oxygen. Will the reactivity of both the isotopes be the same towards oxygen? Justify your answer. Solution: Hydrogen has three isotopes Protium (1H1), Deuterium (2H1), Tritium (3H1). The number of neutrons is the reason why these isotopes differ from each other despite having the same atomic number...
Read More →Find the equation of a line whose inclination with the x
Question: Find the equation of a line whose inclination with the $x$-axis is $30^{\circ}$ and which passes through the point $(0,5)$. Solution: As angle is given so we have to find slope first given by m = tan $m=\tan 30^{\circ}$ $\mathrm{m}=\frac{1}{\sqrt{3}}$ Now the line is passing through the point (0, 5).using slope - intercept form of the equation of the line, we will find the intercept $y=m x+c$ ................(1) $5=\frac{1}{\sqrt{3}}(0)+\mathrm{c} \Rightarrow \mathrm{c}=5$ Putting the ...
Read More →Calculate the strength
Question: Calculate the strength of 5 volume H2O2 solution. Solution: The molar mass of H2O2 is 34gm. According to this reaction, 2 moles of peroxide is involved, so mass becomes 68gm. we know that 1mole of any gas occupies a volume of 22.4L at NTP. Now, 5 volume H2O2 solution means that 1 L of 5 volume H2O2 on decomposition gives 5L of O2 at NTP. 5L of O2 at NTP, we need (68/22.4*5 ) gm H2O2 = 15.179gm. Strength of H2O2 in 5 volumes of it is 15.179gm/L...
Read More →The slope of the tangent to the curve
Question: The slope of the tangent to the curve $x=t^{2}+3 t-8, y=2 t^{2}-2 t-5$ at the point $(2,-1)$ is A. $\frac{22}{7}$ B. $\frac{6}{7}$ C. $\frac{7}{6}$ D. $-\frac{6}{7}$ Solution: Given that $x=t^{2}+3 t-8, y=2 t^{2}-2 t-5$ Differentiating w.r.t. $t$, $\frac{\mathrm{dx}}{\mathrm{dt}}=2 \mathrm{t}+3, \frac{\mathrm{dy}}{\mathrm{dt}}=4 \mathrm{t}-2$ $\frac{\mathrm{dy}}{\mathrm{dx}}=\frac{4 \mathrm{t}-2}{2 \mathrm{t}+3}$ For $(2,-1)$, The given point is $(2,-1)$ $2=t^{2}+3 t-8,-1=2 t^{2}-2 t-5...
Read More →Write one chemical reaction
Question: Write one chemical reaction for the preparation of D2O2 Solution: When D2SO4 reacts with BaO2, D2O2 is formed along with barium sulphate (BaSO4). D2SO4 + BaO2 D2O2 + BaSO4...
Read More →How is heavy water prepared?
Question: How is heavy water prepared? Compare its physical properties with those of ordinary water. Solution: Heavy water, which is deuterium oxide (D2O) is mainly prepared by electrolysis of ordinary water. 1. The molecular mass of ordinary water is 18.015 and that of heavy water is 20.027 2. The melting point of ordinary water is 273.0 and that of heavy water is 276.8 3. The boiling point of ordinary water is 373.0 and that of heavy water is 374.4 4. Density at 298K of ordinary water is 1.000...
Read More →Find the equation of a line
Question: Find the equation of a line which makes an angle of $\frac{2 \pi}{3}$ with the positive direction of the $x-$ axis and passes through the point $(0,2)$ Solution: We have given angle so we have to find slope first given by m = tan. $\mathrm{m}=\tan \theta \Rightarrow \tan \left(\frac{2 \pi}{3}\right)=\tan \left(\pi-\frac{\pi}{3}\right)$ $\mathrm{m} \Rightarrow-\tan \left(\frac{\pi}{3}\right)=-(\sqrt{3})(\tan x$ is negative in $\|$ quadrant $)$ $m=-\sqrt{3}$ Now the line is passing throu...
Read More →The point on the curve
Question: The point on the curve $9 y^{2}=x^{3}$, where the normal to the curve makes equal intercepts with the axes is A. $\left(4, \pm \frac{8}{3}\right)$ B. $\left(-4, \frac{8}{3}\right)$ C. $\left(-4,-\frac{8}{3}\right)$ D. $\left(\frac{8}{3}, 4\right)$ Solution: Given curve $9 y^{2}=x^{3} \ldots$ (1) Differentiate w.r.t. $x$, $18 y \frac{d y}{d x}=3 x^{2}$ $\Rightarrow \frac{d y}{d x}=\frac{x^{2}}{6 y}$ Equation of normal: $\left(\mathrm{y}-\mathrm{y}_{1}\right)=\frac{-1}{\text { Slope of t...
Read More →Find the equation of a line
Question: Find the equation of a line whose slope is - 3 and which passes through the point ( - 2, 3); Solution: As slope is given $m=-3$ and line is passing through point $(-2,3) .$ Using slope - intercept form of equation of line, we will find intercept first $y=m x+c$ ................(1) $3=-3(-2)+c$ $3=6+c$ $c=3-6$ $c=-3$ Putting the value of c in equation (1), we have $y=-3 x+(-3)$ $y=-3 x-3$ $3 x+y+3=0$ So, the required equation of line is 3x + y + 3 = 0....
Read More →Find the equation of a line
Question: Find the equation of a line whose slope is 4 and which passes through the point (5, - 7) Solution: As slope is given $m=4$ and passing through $(5,-7)$.using slope $-$ intercept form of equation of line, we will find value of intercept first $y=m x+c$ ..........(1) $-7=4(5)+c$ $-7=20+c$ $c=-7-20$ $c=-27$ Putting the value of c in equation (1), we have $y=4 x+(-27)$ $y=4 x-27$ $4 x-y-27=0$ So, the required equation of line is $4 x-y-27=0$....
Read More →Any tangent to the curve
Question: Any tangent to the curve $y=2 x^{7}+3 x+5$. A. is parallel to $x$-axis B. is parallel to $y$-axis C. makes an acute angle with $\mathrm{x}$-axis D. makes an obtuse angle with $x$-axis Solution: Given curve $y=2 x^{7}+3 x+5$ Differentiating w.r.t. $x$, $\frac{\mathrm{dy}}{\mathrm{dx}}=14 \mathrm{x}^{6}+3$ Here $\frac{\mathrm{dy}}{\mathrm{dx}} \geq 3$ $\Rightarrow \frac{\mathrm{dy}}{\mathrm{dx}}0$ So, $\tan \theta0$ Hence, $\theta$ lies in first quadrant. So, any tangent to this curve ma...
Read More →Find the equation of a line which is equidistant from the lines
Question: Find the equation of a line which is equidistant from the lines y = 8 and y = - 2. Solution: For the equation of line equidistant from both lines, we will find point through which line passes and is equidistant from both line. As any point lying on $y=8$ line is $(0,8)$ and on $y=-2$ is $(0,-2)$, so mid - point is $(\mathrm{x}, \mathrm{y})=\left(\frac{0+0}{2}, \frac{8-2}{2}\right)$ (x, y) = (0, 3) So, equation of line is y = 3....
Read More →The angle of intersection of the curves
Question: The angle of intersection of the curves $y=2 \sin ^{2} x$ and $y=\cos ^{2} x$ at $x=\frac{\pi}{6}$ is A. $\frac{\pi}{4}$ B. $\frac{\pi}{2}$ C. $\frac{\pi}{3}$ D. $\frac{\pi}{6}$ Solution: Given that the curve $y=2 \sin ^{2} x$ and $y=\cos ^{2} x$ Differentiating both w.r.t. $x$, $\frac{d y}{d x}=4 \sin x \cos x$ and $\frac{d y}{d x}=-2 \cos x \sin x$ $\mathrm{m}_{1}=4 \sin \mathrm{x} \cos \mathrm{x}$ and $\mathrm{m}_{2}=-2 \cos \mathrm{x} \sin \mathrm{x}$ $\operatorname{At} \mathrm{X}=...
Read More →Molecular hydrides are classified as electron-deficient,
Question: Molecular hydrides are classified as electron-deficient, electron precise and electron-rich compounds. Explain each type with two examples. Solution: Molecular hydrides are classified into electron-deficient, electron precise and electron-rich compounds. B2H6 is an electron-deficient hydride. These have an incomplete octet. They are formed generally by the group 13 elements like B, Al, etc. An electron-precise hydride is a type of hydride which has the exact number of electrons require...
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