An aqueous solution of NaCl on electrolysis gives H₂(g), Cl₂(g) and NaOH according to the reaction:
2Cl^- (aq) + 2H₂O = 2OH^- (aq) + H₂ (g) + Cl₂ (g)
A direct current of 25 amperes with a current efficiency of 62 % is passed through 20 litres of NaCl solution (20% by weight). Write down the reactions taking place at the anode and cathode. How long will it take to produce 1kg of Cl₂? What will be the molarity of the solution with respect to hydroxide ion? (Assume no loss due to evaporation)

For the galvanic cell
Ag | AgCl(s), KCl (0.2M) || KBr (0.001M), AgBr(s) | Ag
Calculate the EMF generated and assign correct polarity to each electrode for a spontaneous process after taking into account the cell reaction at 25^oC.
[K_sp(AgCl) = 2.8 $$times$$ 10^-10; K_sp(AgBr) = 3.3 $$times$$ 10^-13]

Zinc granules are added in excess to a 500 ml. of 1.0 M nickel nitrate solution at 25^oC until the equilibrium is reached. If the standard reduction potential of Zn²⁺ | Zn and Ni²⁺ | Ni are -0.75 V and -0.24 V respectively, find out the concentration of Ni²⁺ in solution at equilibrium.

The current of 1.70 A is passed through 300.0 ml of 0.160 M solution of a ZnSO₄ for 230 sec. with a current efficiency of 90%. Find out the molarity of Zn²⁺ after the deposition of Zn. Assume the volume of the solution to remain constant during electrolysis.