Question

Except carbonates and bicarbonates for all other oxo salts solubility in water increases down the group for alkali metals . Explain.

Answer 1

The oxoacids of alkali metals are soluble in water because they have larger hydration energy than lattice energy. Their solubility increase down the group because the lattice energy decreases more rapidly than hydration energy.
In case of oxoacids of alkaline earth metals are insoluble in water because of low hydration energy. On moving down the group, their solubility further decreases because their lattice energy remains constant but hydration energy decreases and hydration energy becomes lower than lattice energy.