Physical Chemistry PYQ — Page 59

$\mathrm{N}_2 \mathrm{O}_5$ decomposes to $\mathrm{NO}_2$ and $\mathrm{O}_2$ and follows first order kinetics. After $50$ minutes, the pressure inside the vessel increases from $50 \mathrm{~mm} \mathrm{~Hg}$ to $87.5 \mathrm{~mm} \mathrm{~Hg}$. The pressure of the gaseous mixture after $100$ minutes at constant temperature will be ______.

For which of the following reactions, $\Delta H$ is equal to $\Delta U$?

The combustion of benzene $(l)$ gives ${\mathrm{CO}}_{2}(g)$ and ${H}_{2}O(l).$ Given that heat of combustion of benzene at constant volume is $-3263.9 \mathrm{kJ} {\mathrm{mol}}^{-1}$ at $25^{\circ}C;$ the heat of combustion $(\mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1})$ of benzene at constant pressure will be $(R=8.314 {\mathrm{JK}}^{-1} {\mathrm{mol}}^{-1})$

An alkali is titrated against acid with methyl orange as an indicator, which of the following is a correct combination?

In which of the following reactions, an increase in the volume of the container will favour the formation of products?

Which of the following is a Lewis acid?

For which of the following processes, $\Delta S$ is negative?

For standardizing $\mathrm{NaOH}$ solution, which of the following is used as a primary standard?

A sample of $\mathrm{NaClO}_3$ is converted by heat to $\mathrm{NaCl}$ with a loss of $0.16 \mathrm{~g}$ of oxygen. The residue is dissolved in water and precipitated as $\mathrm{AgCl}$. The mass of $\mathrm{AgCl}$ (in $\mathrm{g}$) obtained will be: (Given: Molar mass of $\mathrm{AgCl}=143.5 \mathrm{~g} \mathrm{~mol}^{-1}$ )

An ideal gas undergoes a cyclic process as shown in Figure.  $\begin{aligned} &\Delta \mathrm{U}_{\mathrm{BC}}=-5 \mathrm{~kJ} \mathrm{~mol}^{-1}, \mathrm{q}_{\mathrm{AB}}=2 \mathrm{~kJ} \mathrm{~mol}^{-1} \\ &\mathrm{~W}_{\mathrm{AB}}=-5 \mathrm{~kJ} \mathrm{~mol}^{-1}, \mathrm{~W}_{\mathrm{CA}}=3 \mathrm{~kJ} \mathrm{~mol}^{-1} \end{aligned}$ Heat absorbed by the system during process CA is:

Which of the following is a Lewis acid?

An aqueous solution contains an unknown concentration of ${\mathrm{Ba}}^{2+}$. When $50\mathrm{mL}\mathrm{of}a1M$ solution of ${\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$ is added, ${\mathrm{BaSO}}_{4}$ just begins to precipitate. The final volume is $500\mathrm{mL}$. The solubility product of ${\mathrm{BaSO}}_{4}$ is $1\times {10}^{-10}$. What is the original concentration of ${\mathrm{Ba}}^{2+}$?

At 320 K, a gas ${A}_{2}$ is 20 % dissociated to $A(g)$ . The standard Gibbs free energy change at $320 K and 1 atm in J mo{l}^{–1}$ is approximately: $(R = 8.314 {\mathrm{JK}}^{–1} {\mathrm{mol}}^{–1} ;\mathrm{ln}2 = 0.693 ;\mathrm{ln}3 = 1.098)$

The mass of a non-volatile, non-electrolyte solute (molar mass $= 50 g {\mathrm{mol}}^{-1}$) needed to be dissolved in 114 g octane to reduce its vapour pressure by 75 %, is:

At ${518}^{o}C,$ the rate of decomposition of a sample of gaseous acetaldehyde, initially at a pressure of $363 \mathrm{Torr}$ was $1.00 \mathrm{Torr} {s}^{-1}$ when $5%$ had reacted and $0.50 \mathrm{Torr} {s}^{-1}$ when 33% had reacted. The order of the reaction is:

When 9.65 ampere current was passed for 1.0 hour into nitrobenzene in acidic medium, the amount of p-aminophenol produced is:

${N}_{2}{O}_{5}$ decomposes to ${\mathrm{NO}}_{2}$ and ${O}_{2}$ follows the first order kinetics. After $50$ minutes, the pressure inside the vessel increases from $50\mathrm{mm}\mathrm{Hg}$ to $87.5\mathrm{mm}\mathrm{Hg}$. The pressure of the gaseous mixture after $100$ minutes at constant temperature will be:

For per gram of reactant, the maximum quantity of $\mathrm{N}_2$ gas is produced in which of the following thermal decomposition reactions? (Given: Atomic wt. : $\mathrm{Cr}=52 \mathrm{u}, \mathrm{Ba}=137 \mathrm{u}$ ).

When an electric current is passed through acidified water, 112 mL of hydrogen gas at N.T.P was collected at the cathode in 965 seconds. The current passed, in ampere, is:

The minimum volume of water required to dissolve $0.1 \mathrm{~g}$ lead (II) chloride to get a saturated solution $\left(K_{\mathrm{SP}}\right.$ of $\mathrm{PbCl}_2=3.2 \times 10^{-8}$; atomic mass of $\mathrm{Pb}=207 \mathrm{~u})$ is :

For which of the following reactions, $\Delta \mathrm{H}$ is equal to $\Delta \mathrm{U}$ ?

An aqueous solution contains $0.10M {H}_{2}S$ and $0.20M\mathrm{HCl}$. If the equilibrium constant for the formation of ${\mathrm{HS}}^{-}$ from ${H}_{2}S$ is $1.0\times {10}^{-7}$ and that of ${S}^{2-}$ from ${\mathrm{HS}}^{-}$ ions is $1.2\times {10}^{-13}$, then, the concentration of ${S}^{2-}$ ions in the aqueous solution is:

The ratio of mass percent of $C\mathrm{and}H$ of an organic compound $({C}_{X}{H}_{Y}{O}_{Z})$ is $6:1.$ If one molecule of the above compound $({C}_{X}{H}_{Y}{O}_{Z})$ contains half as much oxygen as required to burn one molecule of compound ${C}_{X}{H}_{Y}$ completely to ${\mathrm{CO}}_{2}$ and ${H}_{2}O.$ The empirical formula of the compound ${C}_{X}{H}_{Y}{O}_{Z}$ is

If 50 % of a reaction occurs in 100 second and 75 % of the reaction occurs in 200 second, the order of this reaction is: