Electrochemistry - Physical Chemistry - Chemistry Previous Year Questions

Two statements are given below.

Statement I : Molten NaCl is electrolysed using Pt electrodes. $\mathrm{Cl}_{2}$ is liberated at anode.

Statement II : Aqueous $\mathrm{CuSO}_{4}$ is electrolysed using Pt electrodes. $\mathrm{O}_{2}$ is liberated at cathode.

The correct answer is

0.592 g of copper is deposited in 60 minutes by passing

0.5 A current through a solution of copper (II) sulphate. The electro chemical equivalent of copper (II) (in $\mathrm{gC}^{-1}$ ) is

( $F=96500 \mathrm{C} \mathrm{mol}^{-1}$ )

Electrolysis of aqueous copper (II) sulphate between Pt electrodes gives ' $X^{\prime}$ at anode and ' $Y^{\prime}$ at cathode. $X$ and $Y$ are respectively.

At 298 K , if emf of the cell corresponding to the reaction $\mathrm{Zn}(s)+2 \mathrm{H}^{+}(a q) \longrightarrow \mathrm{Zn}^{2+}(0.01 \mathrm{M})+\mathrm{H}_2(g) (1 \mathrm{~atm})$ is 0.28 V , then the pH of the solution at the hydrogen electrode is $\left(\frac{2.303 R T}{F}=0.06 \mathrm{~V}\right)$, $\left(E_{\mathrm{Zn}^{2+} / \mathrm{Zn}}^{\circ}=-0.76 \mathrm{~V}\right)$

The mole conductivity of acetic acid solution at infinite dilution is $390 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$. What is the molar conductivity of 0.01 M acetic acid solution (in $\mathrm{S} \mathrm{cm}^2 \mathrm{~mol}^{-1}$ )?

(Given $K_a\left(\mathrm{CH}_3 \mathrm{COOH}\right)=1.8 \times 10^{-5}$, assume $1-\alpha=1$ )

The incorrect statement about Castner-kellner cell process is

The Gibbs energy change of the reaction (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) corresponding to the following cell

$\mathrm{Cr}\left|\mathrm{Cr}^{3+}(0.1 \mathrm{M}) \| \mathrm{Fe}^{2+}(0.001 \mathrm{M})\right| \mathrm{Fe}$

(Given $E_{\mathrm{Cr}^{3+} \mid \mathrm{Cr}}^{\circ}=-0.75 \mathrm{~V} ; E_{\mathrm{Fe}^{2+} \mid \mathrm{Fe}}^{\circ}=-0.45 \mathrm{~V}$,

$\left.\mathrm{IF}=96,500 \mathrm{C} \mathrm{mol}^{-1}\right)$

At 298 K the equilibrium constant for the reaction $M(s)+2 \mathrm{Ag}^{+}(a q) \longrightarrow M^{2+}(a q)+2 \mathrm{Ag}(s)$ is $10^{15}$. What is the $E_{\text {cell }}^{\ominus}$ (in V) for this reaction?

$$\left(\frac{2.303 R T}{F}\right)=0.06 \mathrm{~V}$$

The order of negative standard potential values of Li, $\mathrm{Na}, \mathrm{K}$ is

A current of 0.5 ampere is passed through molten $\mathrm{AlCl}_3$ for 96.5 seconds. The mass of aluminium deposited at cathode is $x \mathrm{mg}$ and volume of chlorine liberated (at STP) at anode is $y \mathrm{~mL} . x$ and $y$ are respectively.

Identify the correct statements from the following

(A) At 298 K , the potential of hydrogen electrotle placed in a solution of $\mathrm{pH}=10$, is -0.59 V

(B) The limiting molar conductivity of $\mathrm{Ca}^{2+}$ and $\mathrm{Cl}^{-}$is 119 and $76 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ respectively. The limiting molar conductivity of $\mathrm{CaCl}_2$ is $195 \mathrm{Scm}^2 \mathrm{~mol}^{-1}$

(C) The correct relationship between $K_C$ and $E_{\text {cell }}^{\ominus}$ is \(E_{\text {cell }}^\theta=\frac{2303 R T}{n F} \log K_C\)