Physical Chemistry PYQ — Page 23

The ratio \(\frac{K_P}{K_C}\) for the reaction : \(\mathrm{CO}_{(\mathrm{g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons \mathrm{CO}_{2(\mathrm{~g})}\) is :

The solution from the following with highest depression in freezing point/lowest freezing point is

The number of electrons present in all the completely filled subshells having $n=4$ and $s=+\frac{1}{2}$ is ____ (Where $n=$ principal quantum number and $s=$ spin quantum number)

A sample of ${\mathrm{CaCO}}_{3}$ and ${\mathrm{MgCO}}_{3}$ weighed $2.21g$ is ignited to constant weight of $1.152g$. The composition of the mixture is: (Given molar mass in $g{\mathrm{mol}}^{-1}$, ${\mathrm{CaCO}}_{3}:100,{\mathrm{MgCO}}_{3}:84$)

The equilibrium constant for the reaction \(\mathrm{SO}_3(\mathrm{g}) \rightleftharpoons \mathrm{SO}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g})\) is \(\mathrm{K}_{\mathrm{c}}=4.9 \times 10^{-2}\). The value of \(\mathrm{K}_{\mathrm{c}}\) for the reaction given below is \(2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{SO}_3(\mathrm{~g})\) is :

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency ' \(\mathrm{A}\) ' \(\times 10^{12}\) hertz and that has a radiant intensity in that direction of \(\frac{1}{'\mathrm{~B}^{\prime}}\) watt per steradian. 'A' and 'B' are respectively

 Consider the figure provided. \(1 \mathrm{~mol}\) of an ideal gas is kept in a cylinder, fitted with a piston, at the position A, at \(18^{\circ} \mathrm{C}\). If the piston is moved to position \(\mathrm{B}\), keeping the temperature unchanged, then ' \(x\) ' \(L\) atm work is done in this reversible process. \(x=\) ______ \(\mathrm{L}\) atm. (nearest integer) [Given : Absolute temperature \(={ }^{\circ} \mathrm{C}+273.15, \mathrm{R}=0.08206 \mathrm{~L} \mathrm{~atm} \mathrm{~mol}{ }^{-1} \mathrm{~K}^{-1}\) ]

The mass of sodium acetate $({\mathrm{CH}}_{3}\mathrm{COONa})$ required to prepare $250\mathrm{mL}$ of $0.35M$ aqueous solution is _____ g.$($ Molar mass of ${\mathrm{CH}}_{3}\mathrm{COONa}$ is $82.02g{\mathrm{mol}}^{-1}$) Round off to the nearest integer.

The ratio of $\frac{C14}{C12}$ in a piece of wood is $\frac{1}{8}$ part that of atmosphere. If half life of $C14$ is $5730$ years, the age of wood sample is ..... years.

When ' \(x\) ' \(\times 10^{-2} \mathrm{~mL}\) methanol (molar mass \(=32 \mathrm{~g}\); density \(=0.792 \mathrm{~g} / \mathrm{cm}^3\)) is added to \(100 \mathrm{~mL}\) water (density \(=1 \mathrm{~g} / \mathrm{cm}^3\)), the following diagram is obtained.  \(x=\) ______ (nearest integer). [Given : Molal freezing point depression constant of water at \(273.15 \mathrm{~K}\) is \(1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\)]

Consider the following reaction \[ \mathrm{A}+\mathrm{B} \rightarrow \mathrm{C} \] The time taken for \(\mathrm{A}\) to become \(1 / 4^{\text {th }}\) of its initial concentration is twice the time taken to become \(1 / 2\) of the same. Also, when the change of concentration of \(B\) is plotted against time, the resulting graph gives a straight line with a negative slope and a positive intercept on the concentration axis. The overall order of the reaction is _______

At \(-20^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\) pressure, a cylinder is filled with equal number of \(\mathrm{H}_2, \mathrm{I}_2\) and \(\mathrm{HI}\) molecules for the reaction \(\mathrm{H}_2(\mathrm{~g})+\mathrm{I}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{HI}(\mathrm{g})\), the \(\mathrm{K}_{\mathrm{p}}\) for the process is \(x \times 10^{-1}\). \(\mathrm{x}=\) _____ [Given : \(\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\)]

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

The vapour pressure of pure benzene and methyl benzene at \(27^{\circ} \mathrm{C}\) is given as 80 Torr and 24 Torr, respectively. The mole fraction of methyl benzene in vapour phase, in equilibrium with an equimolar mixture of those two liquids (ideal solution) at the same temperature is _______ \(\times 10^{-2}\) (nearest integer)

Fuel cell, using hydrogen and oxygen as fuels, A. has been used in spaceship B. has as efficiency of \(40 \%\) to produce electricity C. uses aluminum as catalysts D. is eco-friendry E. is actually a type of Galvanic cell only Choose the correct answer from the options given below:

When equal volume of \(1 \mathrm{M} \mathrm{HCl}\) and \(1 \mathrm{M} \mathrm{H}_2 \mathrm{SO}_4\) are separately neutralised by excess volume of \(1 \mathrm{M}\) \(\mathrm{NaOH}\) solution. \(x\) and \(y \mathrm{~kJ}\) of heat is liberated respectively. The value of \(y / x\) is _______

\(2.7 \mathrm{~kg}\) of each of water and acetic acid are mixed. The freezing point of the solution will be \(-x^{\circ} \mathrm{C}\). Consider the acetic acid does not dimerise in water, nor dissociates in water. \(x=\) ______ (nearest integer) [Given: Molar mass of water \(=18 \mathrm{~g} \mathrm{~mol}^{-1}\), acetic acid \(=60 \mathrm{~g} \mathrm{~mol}^{-1}\) \(\mathrm{K}_{\mathrm{f}} \mathrm{H}_2 \mathrm{O}: 1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\) \(\mathrm{K}_{\mathrm{f}}\) acetic acid: \(3.90 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\) freezing point: \(\mathrm{H}_2 \mathrm{O}=273 \mathrm{~K}\), acetic acid \(=290 \mathrm{~K}\)]

For a metal ion, the calculated magnetic moment is $4.90\mathrm{BM}$. This metal ion has _______ number of unpaired electrons

${A}_{2}+{B}_{2}\rightarrow 2\mathrm{AB}.\Delta {H}_{f}=-200\mathrm{kJ}{\mathrm{mol}}^{-1}$ $\mathrm{AB},{A}_{2}$ and ${B}_{2}$ are diatomic molecules. If the bond enthalpies of ${A}_{2},{B}_{2}$ and $\mathrm{AB}$ are in the ratio$1:0.5:1,$ then the bond enthalpy of ${A}_{2}$ is$_________kJ{\mathrm{mol}}^{–1}$ (Nearest integer)

The specific conductance of $0.0025M$ acetic acid is $5\times {10}^{-5}S{\mathrm{cm}}^{-1}$ at a certain temperature. The dissociation constant of acetic acid is ___________ $\times {10}^{-7}$.(Nearest integer) Consider limiting molar conductivity of ${\mathrm{CH}}_{3}\mathrm{COOH}$ as $400S{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}$

Enthalpies of formation of ${\mathrm{CCl}}_{4}(g),{H}_{2}O(g),{\mathrm{CO}}_{2}(g)$ and $\mathrm{HCl}$ are $-105,-242,-394$ and $-92\mathrm{kJ}{\mathrm{mol}}^{-1}$ respectively. The magnitude of enthalpy of the reaction given below is ${\mathrm{kJmol}}^{-1}$. (nearest integer) ${\mathrm{CCl}}_{4}(g)+2{H}_{2}O(g)\rightarrow {\mathrm{CO}}_{2}(g)+4\mathrm{HCl}(g)$

The incorrect statements from the following is: A. The electrical work that a reaction can perform at constant pressure and temperature is equal to the reaction Gibbs energy. B. ${E}_{\mathrm{cell}}^{\circ }$ is dependent on the pressure. C. $\frac{{\mathrm{dE}}_{\mathrm{cell}}^{^{\circ}}}{\mathrm{dT}}=\frac{{\Delta }_{r}{S}^{^{\circ}}}{\mathrm{nF}}$ D. A cell is operating reversibly if the cell potential is exactly balanced by an opposing source of potential difference.

The solubility product of ${\mathrm{BaSO}}_{4}$ is $1\times {10}^{-10}$ at $298K$. The solubility of ${\mathrm{BaSO}}_{4}$ in $0.1M{K}_{2}{\mathrm{SO}}_{4}(\mathrm{aq})$ solution is ------$\times {10}^{-9}g{L}^{-1}$(nearest integer). Given: Molar mass of ${\mathrm{BaSO}}_{4}$ is $233g{\mathrm{mol}}^{-1}$

${\mathrm{KClO}}_{3}+6{\mathrm{FeSO}}_{4}+3{H}_{2}{\mathrm{SO}}_{4}\rightarrow \mathrm{KCl}+3{\mathrm{Fe}}_{2}({\mathrm{SO}}_{4}{)}_{3}+3{H}_{2}O$ The above reaction was studied at $300K$ by monitoring the concentration of ${\mathrm{FeSO}}_{4}$ in which initial concentration was $10M$ and after half an hour became $8.8M$. The rate of production of ${\mathrm{Fe}}_{2}({\mathrm{SO}}_{4}{)}_{3}$ is _______ $\times l{0}^{–6}\mathrm{mol}{L}^{–1}s{}^{–1}$ (Nearest integer)