Question

A divalent element x has a specific heat of 0.106 cal/g/°C. When a solution of the sulphate of x is electrolysed, 4.85g of x is deposited at the cathode and one litre of oxygen gas, measured at 16°C and 743mmHg pressure is evolved at the anode. Calculate the relative atomic mass of x (molar heat capacity =6.4 cal/mol/°C)

Answer 1

reaction of electrolysis:

2XSO₄ + 2H₂O = 2X + 2H₂SO₄ + O₂

n(O₂) = pV/(RT) = 0.041 mol

n(X) = 2n(O₂) = 0.082 mol

M(X) = m(X)/n(X) = 59 g mol^-1