Alkali metal salts ionic and soluble in water. The solubility of an ionic compound depends on (i) lattic ethalpy and (ii) hydration enthalpy. These two factor oppose each other. If hydration ethalpy is high, the ions will have greater tendency to be hydrated and therefore the solubility will be high. The smaller the cation, the greater is the
degree of hydration. The reducing behaviour of alkali metals in
solution is also dependent on the hydration enthalpy besides other factors.
The hydration energy is maximum for

Options

A. `Li^(o+)`
B. `Na^(o+)`
C. `K^(o+)`
D. `Rb^(o+)`

Answer

A

Explanation

`Li^(o+)` ion having the maximum charge density is extensively hydrated ion and thus the energy released, i.e. hydration energy is also the highest.