Physical Chemistry PYQ — Page 56

Given the equilibrium constant: $\mathrm{K}_{\mathrm{C}}$ of the reaction: $\mathrm{Cu}(\mathrm{s})+2 \mathrm{Ag}^{+}(\mathrm{aq}) \rightarrow \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{s})$ is $10 \times 10^{15}$ calculate the $E_{\text {cell }}^{0}$ of this reaction at $298 \mathrm{~K}$ $\left[2.303 \frac{\mathrm{RT}}{\mathrm{F}}\right.$ at $\left.298 \mathrm{~K}=0.059 \mathrm{~V}\right]$

${\wedge }_{m}^{o}$ for $\mathrm{NaCl}, \mathrm{HCl}$ and $\mathrm{NaA}$ are $126.4, 425.9$ and $100.5 S {\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}$ respectively. If the conductivity of $0.001 M \mathrm{HA}$ is $5\times {10}^{-5}S {\mathrm{cm}}^{-1}$, degree of dissociation of $\mathrm{HA}$ is

A solution is prepared by dissolving 0.6 g of urea (molar mass $=60 g mo{l}^{-1}$) and $1.8 g$ of glucose (molar mass $=180 g mo{l}^{-1}$) in 100 mL of water at ${27}^{o}C.$ The osmotic pressure of the solution is: ($R=0.08206 L$$\text{ atm}$ ${K}^{-1} mo{l}^{-1}$)

What would be the molality of 20% (mass/mass) aqueous solution of $KI$ ? (molar mass of $KI=166 g mo{l}^{-1}$ )

$0.27 g$ of a long chain fatty acid was dissolved in $100{ cm}^{3}$ of hexane. $10 mL$ of this solution was added dropwise to the surface of water in a round watch glass. Hexane evaporates and a monolayer is formed. The distance from edge to centre of the watch glass is $10 cm$ . What is the height of the monolayer? [Density of fatty acid $=0.9 g c{m}^{-3};\pi =3]$

For the solution of the gases $w,x,y$ and $z$ in water at $298 K,$ the Henry's law constants $({K}_{H})$ are $0.5,2,35$ and $40 kbar,$ respectively. The correct plot for the given data is:

For the reaction, $2S{O}_{2}(g)+{O}_{2}(g)\rightleftharpoons 2S{O}_{3}(g),$ $\Delta H=-57.2 kJ mo{l}^{-1} and {K}_{c}=1.7\times {10}^{16}.$ Which of the following statements is incorrect?

The ${71}^{\mathrm{st}}$ electron of an element $X$ with an atomic number of $71$ enters the orbital:

Consider the given plot of enthalpy of the following reaction between $A$ and $B.$ $A+B\rightarrow C+D.$ Identify the incorrect statement. 

Two solids dissociate as follows: $A(s)\rightleftharpoons B(g)+C(g); {K}_{{P}_{1}}=x {\mathrm{atm}}^{2}$ $D(s)\rightleftharpoons C(g)+E(g); {K}_{{P}_{2}}=y {\mathrm{atm}}^{2}$ The total pressure when both the solids dissociate simultaneously is:

$20 \mathrm{ml}$ of ${\text{0.1 M H}}_{2}{\mathrm{SO}}_{4}$ solution is added to $30 \mathrm{mL}$ of $0.2 M {\mathrm{NH}}_{4}\mathrm{OH}$ solution. The $\mathrm{pH}$ of the resultant mixture is: $[{\mathrm{pk}}_{b} \mathrm{of} {\mathrm{NH}}_{4}\mathrm{OH}=4.7]$

In the cell, $\mathrm{Pt}(s)|{H}_{2}(g, 1\mathrm{bar})| \mathrm{HCl} (\mathrm{aq})|\mathrm{AgCl}(s)|\mathrm{Ag}(s)|\mathrm{Pt}(s),$the cell potential is $0.92 V$ when a ${10}^{-6}$ molar $\mathrm{HCl}$ solution is used. The standard electrode potential of $\mathrm{Ag}|\mathrm{AgCl}|{\mathrm{Cl}}^{-}$ electrode is: (Given, $\frac{2.303\mathrm{RT}}{F}=0.06 V$ at $298 K$)

For a diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between various thermodynamic quantities?

Consider the reversible isothermal expansion of an ideal gas in a closed system at two different temperatures ${T}_{1}$ and ${T}_{2}({T}_{1}<{T}_{2})$ . The correct graphical depiction of the dependence of work done $(w)$ vs the final volume $(V)$ is:

For the chemical reaction $\mathrm{X} \rightleftharpoons \mathrm{Y},$ the standard reaction Gibbs energy depends on temperature $T$ (in $K$ ) as $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}\left(\right.$ in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)=120-\frac{3}{8} \mathrm{~T}$ The major component of the reaction mixture at $\mathrm{T}$ is :

The freezing point of a diluted milk sample is found to be $-0.2^{\circ} \mathrm{C},$ while it should have been $-0.5^{\circ} \mathrm{C}$ for pure milk. How much water has been added to pure milk to make the diluted sample?

A solution of sodium sulphate contains $92 g$ of ${\mathrm{Na}}^{+}$ ions per kilogram of water. The molality of ${\mathrm{Na}}^{+}$ ions in that solution in $\mathrm{mol} {\mathrm{kg}}^{-1}$ is:

Molecules of benzoic acid $({C}_{6}{H}_{5}\mathrm{COOH})$ dimerise in $30 g$ of benzene. ' $w$ ' $g$ of benzoic acid shows a depression in freezing point equal to $2 K$. If the percentage association of the acid to form dimer in the solution is $80$, then $w$ is: $($ Given that ${K}_{f}=5{\mathrm{Kmol}}^{-1}$, molar mass of benzoic acid $=122 {\mathrm{gmol}}^{-1})$

The electrons are more likely to be found: 

The anodic half-cell of lead-acid battery is recharged using electricity of $0.05$ Faraday. The amount of ${\mathrm{PbSO}}_{4}$ electrolyzed in $g$ during the process is: (Molar mass of ${\mathrm{PbSO}}_{4}=303g {\mathrm{mol}}^{-1}$)

Which one of the following statements regarding Henry's law is not correct?

The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about $9$. The spectral series are:

The freezing point of a $4%$ aqueous solution of $X$ is equal to the freezing point of a $12%$ aqueous solution of $Y$. If the molecular weight of $X$ is $A$, then the molecular weight of $Y$ will be

$N{O}_{2}$ required for a reaction is produced by the decomposition of ${N}_{2}{O}_{5}$ in $CC{l}_{4}$ as per the equation, $2{N}_{2}{O}_{5}(g)\rightarrow 4N{O}_{2}(g)+{O}_{2}(g).$ The initial concentration of ${N}_{2}{O}_{5}$ is $3.00 mol {L}^{-1}$ and it is $2.75 mol {L}^{-1}$ after 30 minutes. The rate of formation of $N{O}_{2}$ is: