• # question_answer The solubility in water of sulphates down the $Be$ group is $Be>Mg>>Ca>Sr>Ba$. This is due to [CBSE PMT 1995] A) High heat of solvation for smaller ions like $B{{e}^{2+}}$ B) Increasing molecular weight C) Decreasing lattice energy D) Increase in melting points

The hydration energy decreases from $B{{e}^{+2}}$ to $B{{a}^{+2}}$. This causes the decrease in the solubilities of the sulphates in this order. In other words, the solubilities decreases with increase in the ionic size.