Why does the solubility of alkaline earth metal hydroxides on water increase down the group.
If hydration energy is greater than lattice energy then the compound is soluble in water.
In case of these hydroxides as we move down the group the difference between the hydration energy and lattice energy goes on increasing thus making the hydroxides more easily soluble.
The observed trend can be explained as follows:
The size of the metal ion increases in the order Be < Mg < Ca < Ba. So, the lattice enthalpy goes on decreasing from Be(OH)2 to Ba(OH)2.
Also, at the same time the hydration energy increases from Be(OH)2 to Ba(OH)2. Therefore, Be(OH)2 is least soluble while Ba(OH)2 is most soluble in water.
In case of these hydroxides as we move down the group the difference between the hydration energy and lattice energy goes on increasing thus making the hydroxides more easily soluble.
The observed trend can be explained as follows:
The size of the metal ion increases in the order Be < Mg < Ca < Ba. So, the lattice enthalpy goes on decreasing from Be(OH)2 to Ba(OH)2.
Also, at the same time the hydration energy increases from Be(OH)2 to Ba(OH)2. Therefore, Be(OH)2 is least soluble while Ba(OH)2 is most soluble in water.