Ammonia is a Lewis base and it forms complexes with many cations. Which one of the following cations does not form a complex with ammonia?

Step-by-step solution

Ammonia is a Lewis base. It forms complexes with transition elements like Ag ⁺, Cu ²⁺ and Cd ²⁺ while it does not form complex with Pb ²⁺ because Pb is not a transition element. AgCl +2 NH ₄ OH [ Ag ( NH ₃ )₂ ] Cl +2 H ₂ O aligned & CuSO ₄+4 NH ₄ OH [ Cu ( NH ₃ )₄ ] SO ₄ +4 H ₂ O aligned aligned & CdSO ₄+4 NH ₄ OH [ Cd ( NH ₃ )₄ ] SO ₄ +4 H ₂ O aligned