Question

Which of the following complexes formed by $Cu^{2+}$ ions is most stable?

• A. $Cu^{2+}+4NH_{3} {\rightleftharpoons} [Cu (NH_{3})_{4}]^{2+}$, $log \,K=11.6$
• B. $Cu^{2+} + 4CN^{-} {\rightleftharpoons} [Cu(CN)_{4}]^{2-}$, $log \,K = 27.3$
• C. $Cu^{2+} + 2en {\rightleftharpoons} [Cu(en)_{2}]^{2+}$, $log \,K = 15.4$
• D. $Cu^{2+} + 4H_{2}O {\rightleftharpoons} [Cu(H_{2}O )_{4}]^{2+}$, $log\, K = 8.9$

Answer 1

Answer: (B)

Higher the value of stability constant $K$, greater is the stability.