Question

what is hydration enthalpy and how does it attribute in reactivity of alkali metals towards water?

Answer 1

Hydration enthalpy may be defined as the energy released when element interact with water molecule. The hydration enthalpy depends upon the size of an atom or ion. It decreases with the increase in atomic or ionic radii. Therefore Lithium have highest hydration energy and shows strong reducing character while this reducing property decreases down the group.