Chemistry - Coordination Chemistry Question with Solution | TestHub
Ligands are neutral or ionic species capable of donating at least one electron pair to central metal. Hence ligands can be of different denticities.
The metal cation that has the least tendency to accept an electron pair from NH₃ is:
Options:
Answer:
Solution:
Explain Question: Identify the metal cation that is the weakest Lewis acid towards ammonia.
Concept: This question is based on Lewis acid-base theory and factors affecting charge density.
Solution:
The tendency to accept an electron pair (Lewis acidity) depends on the cation's charge density, which is the ratio of its charge to its size. A higher charge density means a stronger attraction for electrons and thus a greater tendency to form complexes.
Ba²⁺: This is a large alkaline earth metal ion from Group 2. Although it has a +2 charge, its ionic radius is very large. This results in a very low charge density, giving it the least tendency to attract the electron pair from ammonia.
Therefore, Ba²⁺ is the weakest Lewis acid among the choices and has the least tendency to form a complex with ammonia.
Final answer: Option (D)