S Block Elements Question 29

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

[MP PET 1993; Pb. CET 2000; DPMT 2004]

Options:

A) $ Be>Ca>Mg>Ba>Sr $

B) $ Mg>Be>Ba>Ca>Sr $

C) $ Be>Mg>Ca>Sr>Ba $

D) $ Mg>Ca>Ba>Be>Sr $

Show Answer

Answer:

Correct Answer: C

Solution:

$ Be\ >\ Mg\ >\ Ca\ >\ Sr\ >\ Ba $ On moving down the group lattice energy remains almost constant as the sulphate is so big that small increase in the size of the cations from Be to Ba does not make any difference. However the hydration energy decreases from $ B{{e}^{+2}} $ to $ B{{a}^{+2}} $ . This causes decrease in the solubility of the sulphates as the ionic size increases.