Question

Transition metal complexes containing, $C{N}^{-}$ ligands are often yellow in colour, whereas those containing $H_{2}O$ ligands are often green or blue. This is because $C{N}^{-}$ is a strong ligand. Absorption takes place near $UV$(blue) and so, they appear yellow.
If true enter 1, else enter 0.

Answer 1

$C{N}^{-}$ ligands cause larger energy difference between $d$-orbitals than water ligands. So, cyano complexes have to absorb higher energy photons to cause the transition, therefore, cyano complexes absorb higher energy violet light rather than lower energy red or orange. Hence, cyano complexes are yellow instead of blue or green. Therefore, the correct answer is 1.