Question

Assertion (A): Molality of solution does not change with change in temperature.
Reason (R): Molality is defined as no. of moles of solute per kg of solvent. Which of the following is correct?

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

Answer 1

The correct option is B Both A and R are true and R is not a correct explanation of A

Molality does not change with change in temperature, because it is defined as $\frac{no.of.molesofsolute}{wt.ofsolventinkg}$ . Neither no. of moles nor the wt. of solvent is changing with change in temperature. Hence (b) is the correct option.