Physical Chemistry PYQ — Page 74

To neutralize completely $20 \mathrm{~mL}$ of $0.1 \mathrm{M}$ aqueous solution of phosphorous acid $\left(\mathrm{H}_3 \mathrm{PO}_3\right)$, the volume of $0.1 \mathrm{M}$ aqueous $\mathrm{KOH}$ solution required is

The wavelength of the radiation emitted, when in hydrogen atom electron falls from infinity to stationary state 1 , would be (Rydberg constant $\left.=1.097 \times 10^7 \mathrm{~m}^{-1}\right)$

For the reaction, $\mathrm{CO}(\mathrm{g})+\mathrm{Cl}_2(\mathrm{~g}) \rightleftharpoons \mathrm{COCl}_2(\mathrm{~g})$ the $\frac{\mathrm{K}_{\mathrm{p}}}{\mathrm{K}_{\mathrm{c}}}$ is equal to

An ideal gas expands in volume from $1 \times 10^{-3} \mathrm{~m}^3$ to $1 \times 10^{-2} \mathrm{~m}^3$ at $300 \mathrm{~K}$ against a constant pressure of $1 \times 10^5 \mathrm{Nm}^{-2}$. The work done is

The equilibrium constant for the reaction $\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})$ at temperature $\mathrm{T}$ is $4 \times 10^{-4}$. The value of $\mathrm{Kc}$ for the reaction $\mathrm{NO}(\mathrm{g}) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g})$ at the same temperature is

The rate equation for the reaction $2 \mathrm{~A}+\mathrm{B} \longrightarrow \mathrm{C}$ is found to be: rate $\mathrm{k}[\mathrm{A}][\mathrm{B}]$. The correct statement in relation to this reaction is that the

Which of the following liquid pairs shows a positive deviation from Raoult's law?

The formation of the oxide ion $\mathrm{O}^{2-}(\mathrm{g})$ requires first an exothermic and then an endothermic step as shown below $\mathrm{O}(\mathrm{g})+\mathrm{e}^{-} \mathrm{O}^{-}(\mathrm{g}) \Delta \mathrm{H}^{\circ}=-142 \mathrm{kJmol}^{-1}$ $\mathrm{O}^{-}(\mathrm{g})+\mathrm{e}^{-} \mathrm{O}^{2-}(\mathrm{g}) \Delta \mathrm{H}^{\circ}=844 \mathrm{kJmol}^{-1}$

In hydrogen - oxygen fuel cell, combustion of hydrogen occurs to

What is the equilibrium expression for the reaction $\mathrm{P}_{4(\mathrm{~s})}+5 \mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons \mathrm{P}_4 \mathrm{O}_{10(\mathrm{~s}}$ ?

In first order reaction, the concentration of the reactant decreases from $0.8 \mathrm{M}$ to $0.4 \mathrm{M}$ in 15 minutes. The time taken for the concentration to change from $0.1 \mathrm{M}$ to $0.025 \mathrm{M}$ is

$6.02 \times 10^{20}$ molecules of urea are present in $100 \mathrm{ml}$ of its solution. The concentration of urea solution is

The conjugate base of $\mathrm{H}_2 \mathrm{PO}_4^{-}$is

Consider the following $\mathrm{E}^{\circ}$ values $$ \begin{aligned} & \mathrm{E}_{\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}}^{\circ}=0.77 \mathrm{~V} \\ & \mathrm{E}_{\mathrm{Sn}^{2+} / \mathrm{Sn}}^{\circ}=-0.14 \mathrm{~V} \end{aligned} $$ Under standard conditions the potential for the reaction $\mathrm{Sn}(\mathrm{s})+2 \mathrm{Fe}^{3+}(\mathrm{aq}) \longrightarrow 2 \mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Sn}^{2+}(\mathrm{aq})$ is

Among $\mathrm{Al}_2 \mathrm{O}_3, \mathrm{SiO}_2, \mathrm{P}_2 \mathrm{O}_3$ and $\mathrm{SO}_2$ the correct order of acid strength is

For the reaction equilibrium $\mathrm{N}_2 \mathrm{O}_4(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_2(\mathrm{~g})$ the concentrations of $\mathrm{N}_2 \mathrm{O}_4$ and $\mathrm{NO}_2$ at equilibrium are $4.8 \times 10^{-2}$ and $1.2 \times 10^{-2} \mathrm{~mol} \mathrm{~L}^{-1}$ respectively. The value of $\mathrm{K}_{\mathrm{c}}$ for the reaction is

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $\mathrm{K}_{\mathrm{c}}$ is

When during electrolysis of a solution of $\mathrm{AgNO}_3 9650$ coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be

For the reaction system: $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{NO}_2(\mathrm{~g})$ volume is suddenly reduce to half its value by increasing the pressure on it. If the reaction is of first order with respect to $\mathrm{O}_2$ and second order with respect to $\mathrm{NO}$, the rate of reaction will

In respect of the equation $\mathrm{k}=\mathrm{Ae}^{-\mathrm{E}_{\mathrm{o}} / \mathrm{RT}}$ in chemical kinetics, which one of the following statements is correct?

If liquids $\mathrm{A}$ and $\mathrm{B}$ form an ideal solution

Consider the reaction equilibrium $2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{SO}_3(\mathrm{~g}) ; \Delta \mathrm{H}^0=-198 \mathrm{~kJ}$. On the basis of Le Chatelier's principle, the condition favourable for the forward reaction is

The solubility in water of a sparingly soluble salt $\mathrm{AB}$ is $1.0 \times 10^{-5} \mathrm{~mol} \mathrm{~L}^{-1}$. Its solubility product number will be

If at $298 \mathrm{~K}$ the bond energies of $\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}$ and $\mathrm{H}-\mathrm{H}$ bonds are respectively $414,347,615$ and $435 \mathrm{~kJ}$ $\mathrm{mol}^{-1}$, the value of enthalpy change for the reaction $\mathrm{H}_2 \mathrm{C}=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{H}_3 \mathrm{C}-\mathrm{CH}_3(\mathrm{~g})$ at $298 \mathrm{~K}$ will be