Which of the following complexes has a coordination number of 4?
[Ni(NH₃)4]2+ has 4 NH₃ ligands, giving a coordination number of 4. Others like [Co(NH₃)6]3+ (6) and [Fe(CN)6]4− (6) have higher coordination numbers.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Werner's Theory and Definitions - Ligands Coordination Number