Question

Assertion: $BeS{O}_4$ is soluble in water while $BaS{O}_4$ is not.
Reason : Hydration energy decreases down the group from Be to Ba and lattice energy remains almost constant.

• A. If both assertion and reason are true but reason is not the correct explanation of assertion
• B. If assertion is true but reason is false
• C. If both assertion and reason are true and reason is the correct explanation of assertion
• D. If both assertion and reason are false

Answer 1

The correct option is C If both assertion and reason are true and reason is the correct explanation of assertion

$BeS{O}_4$ is soluble in water whereas $BaS{O}_4$ is not. This is mainly because the hydration energy decreases down the group from Be to Ba and also their lattice energy decrease but remains almost constant. So, on going down the group the hydration energy will be lesser then lattice energy so the solubility decreases down the group.

Hence, option (a) is correct.