The right order of the solubility of sulphates of alkaline earth metals in water is :

Question

The right order of the solubility of sulphates of alkaline earth metals in water is : (A)  Be>Ca>Mg>Ba>Sr  (B)  Mg>Be>Ba>Ca>Sr  (C)  Be>Mg>Ca>Sr>Ba  (D)  Mg>Ca>Ba>Be>Sr

Tardigrade Admin · Accepted Answer

Any compound is soluble in water if lattice energy is less than hydration energy.
The magnitude of lattice energy remains almost constant as the sulphate is so big that small increase in size of cations from

B e

to

B a

does not make any difference.
But hydration energy decreases sufficiently with increase in size from

B e^{2 +}

to

B a^{2 +}

.
As a result solubility of sulphates decreases from

B e

to

B a

with increase in their ionic size.
So the correct order is:

B e > M g > C a > S r > B a

Q. The right order of the solubility of sulphates of alkaline earth metals in water is :

$B e > C a > M g > B a > S r$

$M g > B e > B a > C a > S r$

$B e > M g > C a > S r > B a$

$M g > C a > B a > B e > S r$