Solubility of the alkaline earth's metal sulphates in water decreases in the sequence

Question

Solubility of the alkaline earth's metal sulphates in water decreases in the sequence (A) Sr > Ca > Mg > Ba (B) Ba > Mg > Sr > Ca (C) Ca > Sr > Ba > Mg (D) Mg > Ca > Sr > Ba

Tardigrade Admin · Accepted Answer

On moving down the group size of cation increases so hydration energy decreases and solubility decreases as lattice energy dominates over hydration energy.
Due to very small size of

M g^{+ 2}, M g^{+ 2}

shows maximum hydration energy and

M g S O_{4}

is more soluble here.
Solution

Q. Solubility of the alkaline earth's metal sulphates in water decreases in the sequence

Sr > Ca > Mg > Ba

Ba > Mg > Sr > Ca

Ca > Sr > Ba > Mg

Mg > Ca > Sr > Ba

On moving down the group size of cation increases so hydration energy decreases and solubility decreases as lattice energy dominates over hydration energy. Due to very small size of Mg+2,Mg+2 shows maximum hydration energy and MgSO4​ is more soluble here.

On moving down the group size of cation increases so hydration energy decreases and solubility decreases as lattice energy dominates over hydration energy.
Due to very small size of $M g^{+ 2}, M g^{+ 2}$ shows maximum hydration energy and $M g S O_{4}$ is more soluble here.