Question

Which of the following is temperature independent?

• A. Molality
• B. Molarity
• C. Normality
• D. None of these

Hint:

Terms based on mass are temperature independent; terms based on volume are not.

Answer 1

The Correct Option is A

Step 1: Recall the definitions.
Molality \( = \dfrac{\text{moles of solute}}{\text{mass of solvent in kg}} \). Molarity \( = \dfrac{\text{moles of solute}}{\text{volume of solution in L}} \). Normality \( = \dfrac{\text{gram equivalents}}{\text{volume of solution in L}} \).

Step 2: See which quantities change with temperature.
Mass does not change with temperature, but volume of a solution expands or contracts as temperature changes.

Step 3: Apply this.
Molarity and Normality use volume, so they change with temperature. Molality uses only masses (moles and kg of solvent), so it is independent of temperature.

Conclusion: Molality is temperature independent. Option (i).
\[\boxed{\text{Molality}}\]