In the separation of `Cu^(2+) and Cd^(2+)` in II group qualitative analysis of cations tetramine copper (II) sulphate and tetramine cadium (II) sulphate react with KCN to form the corresponding cyano complexes. Which one of the following pairs of the complexes and their relative stability enables the separation of `Cu^(2+) and Cd^(2+)`?

Options

A. `K_(3)[Cu(CN)_(4)]` is perfect and `K_(2)[Cd(CN)_(4)]` is inperfect complex
B. `K_(3)[CN)_(4)] and K_(2)[Cd(CN)_(4)]` is perfect complex
C. `K_(2)[Cu(CN)_(4)]` inperfect and `K_(2)[Cd(CN)_(4)]` perfect complex
D. `K_(3)[Cu(CN)_(4)]` inperfect and `K_(2)[Cd(CN)_(4)]` is perfect complex

Answer

A