Which of the following complexes is/are heteroleptic?

(a) CoNH363+
(b) Fe(NH3)4Cl2+
(c) Mn(CN)64-
(d) Co(NH3)4Cl2

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (b, d)

Heteroleptic complexes Coordination complexes that contain more than one type of ligands are known as heteroleptic complexes.

eg, Fe(NH3)4Cl2+ contain NH, and Cl as a ligand is a heteroleptic complex. Similarly, Co(NH3)4Cl2 contain NH3 and Cl as ligand is also a heteroleptic complex

Hence, optons (b) and (d) are correct choices.