ln quantitative analysis of second group in laboratory, H2S gas is passed in acidic medium for precipitation' When Cu2+ and Cd2+ react with KCN, then for product true statement is

In K3[Cu(CN)2] copper is in + 1 oxidation state while in K2[Cd(CN)2] cadmium is in +2 oxidation state. The more the oxidation state of the central metal atom, the more is the stability of the complex.