The hydration energy of Mg2+ ion is less than that of

Correct option is A

Hydration energy refers to the energy released when an ion is surrounded by water molecules during the hydration process. The hydration energy of an ion depends on its charge density, which is influenced by the ion's charge and radius.
The Mg²⁺ ion has a lower hydration energy compared to Al³⁺ because:
1. Al³⁺ has a higher charge (3+) compared to Mg²⁺ (2+), resulting in greater attraction to water molecules.
2. The smaller ionic radius of Al³⁺ further increases its charge density compared to Mg²⁺.
Al³⁺ has a greater charge-to-size ratio, causing it to interact more strongly with water molecules, releasing more hydration energy.
Additional Knowledge:
· Ba²⁺: Ba²⁺ has a much larger ionic radius compared to Mg²⁺, which reduces its charge density and hydration energy.
· Na⁺: Na⁺ has a single positive charge (1+), resulting in lower hydration energy compared to Mg²⁺. It has a larger radius than Mg²⁺ but lower charge.