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+),logK=11.6`
B. `Cu^(2+)+4CN^(-)hArr [Cu(CN)_(4)]^(2-),logK=27.3`
C. `Cu^(2+)+2en hArr [Cu(en)_(3)]^(2+), logK=15.4`
D. `Cu^(2+)+4H_(2)OhArr [Cu(H_(2)O)_(4)]^(2+), logK=8.9`

Answer

B

Explanation

Stability increases as the value of K and hence log K increases.