Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : $LiF$ is sparingly soluble in water.
Reason R : The ionic radius of $Li^+$ ion is smallest among its group members, hence has least hydration enthalpy.
In the light of the above statements, choose the most appropriate answer from the options given below.

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

Answer: (C)

A is true but R is false.

Answer 2

$LiF$ is sparingly soluble in water.

The low solubility of $LiF$ in water is due to its high lattice enthalpy (Since $Li^+$ and $F^-$ are small in size). Also, due to small size of $Li^+$, its hydration enthalpy is high.

Hence, Assertion is true, but Reason is false.