Question

From the stability constant (hypothetical values) given below, predict which is the strongest ligand?

• A. $C{u}^{2+}+4N{H}_3\to \left[Cu\right(N{H}_3{)}_4{]}^{2+},K=4.5\times {10}^{11}$
• B. $C{u}^{2+}+4C{N}^{-}\to \left[Cu\right(CN{)}_4{]}^{2-},K=2.0\times {10}^{27}$
• C. $C{u}^{2+}+2en\to \left[Cu\right(en{)}_2{]}^{2+},K=3.0\times {10}^{15}$
• D. $C{u}^{2+}+4H_{2}O\to \left[Cu\right(H_{2}O{)}_4{]}^{2+},K=9.5\times {10}^8$

Answer 1

The correct option is B $C{u}^{2+}+4C{N}^{-}\to \left[Cu\right(CN{)}_4{]}^{2-},K=2.0\times {10}^{27}$

As $C{N}^{-}$ is the strongest ligand among all and stability constant is maximum for it.

$C{u}^{2+}+4C{N}^{-}\to \left[Cu\right(CN{)}_4{]}^{2-},K=2.0\times {10}^{27}$.

So, it is most stable among all.