Physical Chemistry PYQ — Page 33

A radioactive element has a half life of $200$ days. The percentage of original activity remaining after $83$ days is____(Nearest integer) (Given : antilog $0.125=1.333$, antilog $0.693=4.93$)

The resistance of a conductivity cell containing $0.01\mathrm{MKCl}$ solution at $298K$ is $1750\Omega$. If the conductivity of $0.01\mathrm{MKCl}$ solution at $298K$ is $0.152\times {10}^{-3}S{\mathrm{cm}}^{-1}$, then the cell constant of the conductivity cell is____$\times {10}^{-3}{\mathrm{cm}}^{-1}$

Given below are the quantum numbers for $4$ electrons. A. $n=3,l=2,{m}_{1}=1,{m}_{s}=+\frac{1}{2}$ B. $n=4,l=1,{m}_{1}=0,{m}_{s}=+\frac{1}{2}$ C. $n=4,l=2,{m}_{1}=-2,{m}_{s}=-\frac{1}{2}$ D. $n=3,l=1,{m}_{1}=-1,{m}_{s}=+\frac{1}{2}$ The correct order of increasing energy is

A $0.5$ percent solution of potassium chloride was found to freeze at $-0.24^{\circ}C$. The percentage dissociation of potassium chloride is (Nearest integer) (Molal depression constant for water is $1.80K\mathrm{kg}{\mathrm{mol}}^{-1}$ and molar mass of $\mathrm{KCl}$ is $74.6g{\mathrm{mol}}^{-1}$)

Match List-I with List-II. <table class="pyq-table"><tbody><tr><td></td><td>List-I</td><td></td><td>List-II</td></tr><tr><td>A</td><td>$\mathrm{Cd}(s)+2\mathrm{Ni}{(\mathrm{OH})}_{3}(s)\rightarrow \mathrm{CdO}(s)+2\mathrm{Ni}{(\mathrm{OH})}_{2}(s)+{H}_{2}O(l)$</td><td>I</td><td>Primary battery</td></tr><tr><td>B</td><td>$\mathrm{Zn}(\mathrm{Hg})+\mathrm{HgO}(s)\rightarrow \mathrm{ZnO}(s)+\mathrm{Hg}(l)$</td><td>II</td><td>Discharging of secondary battery</td></tr><tr><td>C</td><td>$2{\mathrm{PbSO}}_{4}(s)+2{H}_{2}O(I)\rightarrow \mathrm{Pb}(s)+{\mathrm{PbO}}_{2}(s)+2{H}_{2}{\mathrm{SO}}_{4}(\mathrm{aq})$</td><td>III</td><td>Fuel cell</td></tr><tr><td>D</td><td>$2{H}_{2}(g)+{O}_{2}(g)\rightarrow 2{H}_{2}O(l)$</td><td>IV</td><td>Charging of secondary battery</td></tr></tbody></table>Choose the correct answer from the options given below

While performing a thermodynamics experiment, a student made the following observations, $\mathrm{HCl}+\mathrm{NaOH}\rightarrow \mathrm{NaCl}+{H}_{2}O\Delta H=-57.3\mathrm{kJ}{\mathrm{mol}}^{-1}$ ${\mathrm{CH}}_{3}\mathrm{COOH}+\mathrm{NaOH}\rightarrow {\mathrm{CH}}_{3}\mathrm{COONa}+{H}_{2}O$ $\Delta H=-55.3\mathrm{kJ}{\mathrm{mol}}^{-1}$. The enthalpy of ionization of ${\mathrm{CH}}_{3}\mathrm{COOH}$ as calculated by the student is $\mathrm{kJ}{\mathrm{mol}}^{-1}$.

For a first order reaction, the time required for completion of $90%$ reaction is '$x$' times the half life of the reaction. The value of '$x$' is (Given: $\mathrm{ln}10=2.303$ and $\mathrm{log}2=0.3010$)

The solubility of $\mathrm{AgCl}$ will be maximum in which of the following?

In base vs. Acid titration, at the end point methyl orange is present as

If the radius of the ${3}^{\mathrm{nd}}$ Bohr's orbit of hydrogen atom is ${r}_{3}$ and the radius of ${4}^{\mathrm{th}}$ Bohr's orbit is ${r}_{4}$. Then

A $2.0g$ sample containing ${\mathrm{MnO}}_{2}$ is treated with $\mathrm{HCl}$ liberating ${\mathrm{Cl}}_{2}$. The ${\mathrm{Cl}}_{2}$ gas is passed into a solution of $\mathrm{KI}$ and $60.0\mathrm{mL}$ of $0.1{\mathrm{MNaS}}_{2}{O}_{3}$ is required to titrate the liberated iodine. The percentage of ${\mathrm{MnO}}_{2}$ in the sample is____. Nearest integer) [Atomic masses (in $u$) $\mathrm{Mn}=55;\mathrm{Cl}=35.5:O=16,I=127,\mathrm{Na}=23,K=39,S=32$]

$150g$ of acetic acid was contaminated with $10.2g$ ascorbic acid $({C}_{6}{H}_{8}{O}_{6})$ to lower down its freezing point by $(x\times {10}^{-1})^{\circ}C$. The value of $x$ is____ (Nearest integer). [Given ${K}_{f}=3.9K\mathrm{kg}{\mathrm{mol}}^{-1}$; Molar mass of ascorbic acid $=176g{\mathrm{mol}}^{-1}$]

The ${K}_{\mathrm{sp}}$ for bismuth sulphide $({\mathrm{Bi}}_{2}{S}_{3})$ is $1.08\times {10}^{-73}$. The solubility of ${\mathrm{Bi}}_{2}{S}_{3}$ in ${\mathrm{molL}}^{-1}$ at $298K$ is

$A$ fish swimming in water body when taken out from the water body is covered with a film of water of weight $36g$. When it is subjected to cooking at $100^{\circ}C$, then the internal energy for vaporization in ${\mathrm{kJmol}}^{-1}$ is integer] [Assume steam to be an ideal gas. Given ${\Delta }_{\mathrm{vap}}{H}^{\ominus }$ for water at $373K$ and $1$ bar is $41.1\mathrm{kJ}{\mathrm{mol}}^{-1}:R=8.31J{K}^{-1}{\mathrm{mol}}^{-1}$]

A gaseous mixture of two substances $A$ and $B$, under a total pressure of $0.8\mathrm{atm}$ is in equilibrium with an ideal liquid solution. The mole fraction of substance $A$ is $0.5$ in the vapour phase and $0.2$ in the liquid phase. The vapour pressure of pure liquid $A$ is____atm.(Nearest integer)

$C(s)+{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g)+400\mathrm{kJ}$ $C(s)+\frac{1}{2}{O}_{2}(g)\rightarrow \mathrm{CO}(g)+100\mathrm{kJ}$ When coal of purity $60%$ is allowed to burn in presence of insufficient oxygen, $60%$ of carbon is converted into ' $\mathrm{CO}$' and the remaining is converted into '${\mathrm{CO}}_{2}$'. The heat generated when $0.6\mathrm{kg}$ of coal is burnt is

The correct decreasing order of energy, for the orbitals having, following set of quantum numbers: (A) $n=3,1=0,m=0$ (B) $n=4,l=0,m=0$ (C) $n=3,l=1,m=0$ (D) $n=3,1=2,m=1$

At $30^{\circ}C$, the half life for the decomposition of ${\mathrm{AB}}_{2}$ is $200s$ and is independent of the initial concentration of ${\mathrm{AB}}_{2}$. The time required for $80%$ of the ${\mathrm{AB}}_{2}$ to decompose is (Given: $\mathrm{log}2=0.30$; $\mathrm{log}3=0.48$)

Which of the following is the correct plot for the probability density ${\psi }^{2}(r)$ as a function of distance $'r'$ of the electron form the nucleus for $2s$ orbital?

For a given chemical reaction ${\gamma }_{1}A+{\gamma }_{2}B\rightarrow {\gamma }_{3}C+{\gamma }_{4}D$. Concentration of $C$ changes from $10\mathrm{mmol}{\mathrm{dm}}^{-3}$ to $20\mathrm{mmol}{\mathrm{dm}}^{-3}$ in $10s.$ Rate of appearance of $D$ is $1.5$ times the rate of disappearance of $B$ which is twice the rate of disappearance $A$. The rate of appearance of $D$ has been experimentally determined to be $9\mathrm{mmol}{\mathrm{dm}}^{-3}{s}^{-1}.$ Therefore the rate of reaction is____$\mathrm{mmol}{\mathrm{dm}}^{-3}{s}^{-1}.$ (Nearest Integer)

In $3d$ series, the metal having the highest ${M}^{2+}/M$ standard electrode potential is

The amount of charge in $F$ (Faraday) required to obtain one mole of iron from ${\mathrm{Fe}}_{3}{O}_{4}$ is ______. (Round off the answer to the nearest integer)

On complete combustion $0.30g$ of an organic compound gave $0.20g$ of carbon dioxide and $0.10g$ of water. The percentage of carbon in the given organic compound is____(Nearest Integer)

For a first order reaction, the half-life is 10 minutes. What fraction of reactant remains after 40 minutes?