MCQ
Which of the following complexes formed by $\mathrm{Cu}^{2+}$ ions is most stable?
- A$\text{Cu}^{2+} + 4\text{NH}_3\rightleftharpoons[\text{Cu}(\text{NH}_3)_4]^{2+},\ \log\text{K} = 11.6$
- ✓$\text{Cu}^{2+} + 4\text{CN}^-\rightleftharpoons[\text{Cu}(\text{CN})_4]^{2-},\ \log\text{K} = 27.3$
- C$\text{Cu}^{2+} + 2\text{en}\rightleftharpoons[\text{Cu}(\text{en})_2]^{2+},\ \log\text{K} = 15.4$
- D$\text{Cu}^{2+} +4\text{H}_2\text{O}\rightleftharpoons[\text{Cu}(\text{H}_2\text{O})_4]^{2+},\ \log\text{K} = 8.9$