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)

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

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?