Physical Chemistry PYQ — Page 32

Maximum number of electrons that can be accommodated in shell with $n=4$ are:

Consider the following equation: $2{\mathrm{SO}}_{2}(g)+{O}_{2}(g)\rightleftharpoons 2{\mathrm{SO}}_{3}(g),\Delta H=-190\mathrm{kJ}$. The number of factors which will increase the yield of ${\mathrm{SO}}_{3}$ at equilibrium from the following is _____ . A. Increasing temperature B. Increasing pressure C. Adding more ${\mathrm{SO}}_{2}$ D. Adding more ${O}_{2}$ E. Addition of catalyst

For a first order reaction $A\rightarrow B$, the rate constant, $k=5.5\times {10}^{-14}{s}^{-1}$. The time required for $67%$ completion of reaction is $x\times {10}^{-1}$ times the half life of reaction. The value of $x$ is Nearest integer) (Given : $\mathrm{log}3=0.4771$)

Number of grams of bromine that will completely react with $5.0g$ of pent-$1$-ene is____$\times {10}^{-2}g$. (Atomic mass of $\mathrm{Br}=80g/\mathrm{mol}$) [Nearest integer]

Boiling point of a $2%$ aqueous solution of a nonvolatile solute $A$ is equal to the boiling point of $8%$ aqueous solution of a non-volatile solute $B$. The relation between molecular weights of $A$ and $B$ is.

For the decomposition of azomethane. ${\mathrm{CH}}_{3}{N}_{2}{\mathrm{CH}}_{3}(g)\rightarrow {\mathrm{CH}}_{3}{\mathrm{CH}}_{3}(g)+{N}_{2}$ a first order reaction, the variation in partial pressure with time at $600K$ is given as  The half life of the reaction is____$\times {10}^{-5}s$

$0.01{\mathrm{MKMnO}}_{4}$ solution was added to $20.0\mathrm{mL}$ of $0.05M\mathrm{Mohr}$ 's salt solution through a burette. The initial reading of $50\mathrm{mL}$ burette is zero. The volume of ${\mathrm{KMnO}}_{4}$ solution left in the burette after the end point is....... $\mathrm{mL}$. (nearest integer)

For the reaction ${H}_{2}{F}_{2}(g)\rightarrow {H}_{2}(g)+{F}_{2}(g)$ $\Delta U=-59.6\mathrm{kJ}{\mathrm{mol}}^{-1}$ at $27^{\circ}C$ The enthalpy change for the above reaction is $(-)$____ ${\mathrm{kJmol}}^{-1}$ (nearest integer) (Given : $R=8.314{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$) .

The complete combustion of $0.492g$ of an organic compound containing '$C$', '$H$' and '$O$' gives $0.793g$ of ${\mathrm{CO}}_{2}$ and $0.442g$ of ${H}_{2}O$. The percentage of oxygen composition in the organic compound is____.(nearest integer)

$1.80g$ of solute A was dissolved in $62.5{\mathrm{cm}}^{3}$ of ethanol and freezing point of the solution was found to be $155.1K$. The molar mass of solute $A$ is ${\mathrm{gmol}}^{-1}$. [Given: Freezing point of ethanol is $156.0K$. Density of ethanol is $0.80g{\mathrm{cm}}^{-3}$. Freezing point depression constant of ethanol is $2.00K\mathrm{kg}{\mathrm{mol}}^{-1}$]

The limiting molar conductivities of $\mathrm{NaI},{\mathrm{NaNO}}_{3}$ and ${\mathrm{AgNO}}_{3}$ are $12.7,12.0$ and $13.3{\mathrm{mSm}}^{2}{\mathrm{mol}}^{-1}$, respectively (all at $25^{\circ}C$). The limiting molar conductivity of $\mathrm{AgI}$ at this temperature is____${\mathrm{mSm}}^{2}{\mathrm{mol}}^{-1}$.

The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is: [Given: The threshold frequency of platinum is $1.3\times {10}^{15}{s}^{-1}$ and $h=6.6\times {10}^{-34}\mathrm{Js}$]

${N}_{2(g)}+3{H}_{2(g)}\rightleftharpoons 2{\mathrm{NH}}_{3(g)} 20g5g$ Consider the above reaction. If $20$g of dinitrogen reacts with $5$g of dihydrogen, then the limiting reagent of the reaction and number of moles of ${\mathrm{NH}}_{3}$ formed respectively are

At $25^{\circ}C$ and $1\mathrm{atm}$ pressure, the enthalpy of combustion of benzene $(1)$ and acetylene $(g)$ are $-3268\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $-1300\mathrm{kJ}{\mathrm{mol}}^{-1}$, respectively. The change in enthalpy for the reaction $3{C}_{2}{H}_{2}(g)\rightarrow {C}_{6}{H}_{6}(l)$, is

$40%$ of $\mathrm{HI}$ undergoes decomposition to ${H}_{2}$ and ${I}_{2}$ at $300K.{\Delta G}^{\Theta }$ for this decompostion reaction at one atmopsphere pressure is____${\mathrm{Jmol}}^{-1}$-[nearest integer] $(\mathrm{Use}R=8.31{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1};\mathrm{log}2=0.3010,\mathrm{ln}10=2.3,\mathrm{log}3=0.477)$

If a rocket runs on a fuel $({C}_{15}{H}_{30})$ and liquid oxygen, the weight of oxygen required and ${\mathrm{CO}}_{2}$ released for every litre of fuel respectively are : (Given : density of the fuel is $0.756g/\mathrm{mL}$)

The Plot of $\mathrm{pH}$-metric titration of weak base ${\mathrm{NH}}_{4}\mathrm{OH}$ vs strong acid $\mathrm{HCl}$ looks like

The minimum uncertainty in the speed of an electron in one dimensional region of length $2{a}_{o}$ (Where ${a}_{o}=$ Bohr radius $52.9\mathrm{pm}$) is____${\mathrm{kms}}^{-1}$ (Nearest integer) (Given : Mass of electron $=9.1\times {10}^{-31}\mathrm{kg}$, Planck's constant $h=6.63\times {10}^{-34}\mathrm{Js}$)

The elevation in boiling point for $1$ molal solution of non-volatile solute $A$ is $3K$. The depression in freezing point for $2$ molal solution of $A$ in the same solvent is $6K$. The ratio of ${K}_{b}$ and ${K}_{f}$ i.e., ${K}_{b}/{K}_{f}$ is $1:X$. The value of $X$ is

$\begin{matrix}[A] & \rightarrow & [B] \\ \mathrm{Reactant} & & \mathrm{Product}\end{matrix}$ If formation of compound $[B]$ follows the first order of kinetics and after $70$ minutes the concentration of $[A]$ was found to be half of its initial concentration. Then the rate constant of the reaction is $x\times {10}^{-6}{s}^{-1}$. The value of $x$ is____

When a certain amount of solid $A$ is dissolved in $100g$ of water at $25^{\circ}C$ to make a dilute solution, the vapour pressure of the solution is reduced to one-half of that of pure water. The vapour pressure of pure water is $23.76\mathrm{mmHg}$. The number of moles of solute $A$ added is

Hemoglobin contains $0.34%$ of iron by mass. The number of $\mathrm{Fe}$ atoms in $3.3g$ of hemoglobin is (Given : Atomic mass of Fe is $56u,{N}_{A}$ in$6.022\times {10}^{23}{\mathrm{mol}}^{-1}$)

$56.0L$ of nitrogen gas is mixed with excess of hydrogen gas and it is found that $20L$ of ammonia gas is produced, The volume of unused nitrogen gas is found to be_____ $L$.

Compound $A$ contains $8.7%$ Hydrogen, $74%$ Carbon and $17.3%$ Nitrogen. The molecular formula of the compound is, Given : Atomic masses of $C,H$ and $N$ are $12,1$ and $14$ amu respectively. The molar mass of the compound $A$ is $162g{\mathrm{mol}}^{-1}$.