Which of the following complexes formed by `Cu^(2+)` ions is most stable ?

Options

A. `Cu^(2+) + 4NH_3 hArr [Cu(NH_3)_4]^(2+) , log K = 11.6 `
B. `Cu^(2+) + 4CN^(-) hArr [Cu(CN)_4]^(2-) , log K = 27.3`
C. `Cu^(2+) + 2en hArr [Cu(en)_2]^(2+) , log K = 15.4`
D. `Cu^(2+) + 4H_2O hArr [Cu(H_2O)_4]^(2+), log K = 8.9`

Answer

B

Explanation

Higher the value of log K, greater is the stability of the complex.