Which of the following complexes formed by Cu2+ ions is most stable?

Question

Which of the following complexes formed by Cu2+ ions is most stable? (A) Cu2++4NH3 leftharpoons [Cu (NH3)4]2+, log K=11.6 (B) Cu2+ + 4CN- leftharpoons [Cu(CN)4]2-, log K = 27.3 (C) Cu2+ + 2en leftharpoons [Cu(en)2]2+, log K = 15.4 (D) Cu2+ + 4H2O leftharpoons [Cu(H2O )4]2+, log K = 8.9

Tardigrade Admin · Accepted Answer

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

Q. Which of the following complexes formed by $C u^{2 +}$ ions is most stable?

$C u^{2 +} + 4 N H_{3} ⇌ [C u (N H_{3})_{4}]^{2 +}$ , $l o g K = 11.6$

$C u^{2 +} + 4 C N^{-} ⇌ [C u (CN)_{4}]^{2 -}$ , $l o g K = 27.3$

$C u^{2 +} + 2 e n ⇌ [C u (e n)_{2}]^{2 +}$ , $l o g K = 15.4$

$C u^{2 +} + 4 H_{2} O ⇌ [C u (H_{2} O)_{4}]^{2 +}$ , $l o g K = 8.9$

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

Q. Which of the following complexes formed by Cu2+ ions is most stable?

Cu2++4NH3​⇌[Cu(NH3​)4​]2+, logK=11.6

Cu2++4CN−⇌[Cu(CN)4​]2−, logK=27.3

Cu2++2en⇌[Cu(en)2​]2+, logK=15.4

Cu2++4H2​O⇌[Cu(H2​O)4​]2+, logK=8.9