Question

Assertion: $Na _{2} SO _{4}$ is soluble in water while $BaSO _{4}$ is not.
Reason: Lattice energy of $BaSO _{4}$ exceeds its hydration energy.

• A. If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion
• B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion
• C. If Assertion is true but the Reason is false
• D. If both Assertion and Reason are false

Answer 1

Answer: (A)

The large sized sulphate anion $(SO_4 ^{2-} )$ is stabilised better by a large sized cation. So the stability of sulphates down the group, increases. In other words lattice energy is more down the group.