Section-D: Comprehension Type
Comprehension (s-Block Element)
The solubility of most salt depends on the lattice energy of the solid and the hydration energy of the ions. On descending the group, the hydration energy decreases more rapidly then the lattice energy, hence the compound become less soluble as the metals gets larger. However, with the fluorides and hydroxides the lattice energy decreases more rapidly than the hydration energy and so their solubility increases on descending the group.
The most soluble hydroxide will be