Electrochemistry - Physical Chemistry - Chemistry Previous Year Questions

A solution of copper sulphate is electrolyzed between copper electrodes by a current of 10.0A passing for one hour. Which of the following statements is correct regarding the changes occur at the electrodes and in the solution?

The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 A is (Atomic mass of Ca = 40)

The molar conductivities of KCl, NaCl and KNO₃ are 152, 128 and 111 S cm² mol^\(-\)1 respectively. What is the molar conductivity of NaNO₃?

Given, the reduction potential of Na⁺, Mg²⁺, Al³⁺ and Ag⁺ as \(E_{N{a^ + }/Na}^o\) = \(-\) 2.17 V; \(E_{M{g^{2 + }}/Mg}^o\) = \(-\) 2.37 V; \(E_{A{g^ + }/Ag}^o\) = \(-\) 0.08 V.

The least stable oxide is

Using the standard electrode potential, find out the pair between which redox reaction is not feasible.

E\(^\Theta\) values Fe³⁺ / Fe²⁺ = + 0.77; I₂ / I^\(-\) = + 0.54 Cu²⁺ / Cu = + 0.34; Ag⁺ / Ag = 0.80 V

The equilibrium constant of the reaction

$$A(s)+2 B^{+}(a q) \rightleftharpoons A^{2+}(a q)+2 B(s)$$

$$E_{\text {cell }}^{\circ}=0.0295 \mathrm{~V} \text { is } \quad\left[\frac{2.303 R T}{F}=0.059\right]$$

The approximate time duration in hours to electroplate 20 g of calcium from molten calcium chloride using a current of 4 A is (Atomic mass of $\mathrm{Ca}=40$ )

A current of 4.0 A is passed through 0.5 L of 0.2 M NaCl solution for 1200 s . Calculate the pH of the solution after electrolysis.