Calculate the mass of hydrated copper sulphate required to produce 56.90 g of the complex compound assuming other reagents to be present in excess.
CuSO4.5H2O→CuSO4+5H2O
CuSO4+2KCN→Cu(CN)2+K2SO4
2Cu(CN)2→2CuCN+(CN)2
2CuCN+6KCN→2K3[Cu(CN)4]
(Molar mass of K=39 g/mol, Cu=63.5 g/mol)