A current is passed through three electrolytic cells connected in series containing solution of silver trioxonitrate(V),copper(II)tetraoxosulphate(VI) and brine respectively. if 12.7 g of copper are deposited in the second electolytic cell, calculate a. the mass of silver deposited in the first cell, b. the volume of chlorine liberated in the third cell at 16°C and 800 mm Hg pressure.(Ag = 108, Cu =63.5, 1 F = 96500 C, G.M.V of gases at s.t.p = 22.4 dm³​