Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A) : At $10^{\circ} C$, the density of a $5 \,M$ solution of $KCl$ [atomic masses of $K$ and $Cl$ are $39$ & $35.5 \,g \,mol ^{-1}$. The solution is cooled to $-21^{\circ} C$. The molality of the solution will remain unchanged.
Reason (R) : The molality of a solution does not change with temperature as mass remains unaffected with temperature.
In the light of the above statements, choose the correct 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: (A)

Molality is independent of temperature and hence both assertion and reason are true.