Question

Which of the following does not depend upon the temperature

• A. a) molarity
• B. b) normality
• C. c) formality
• D. d) molality

Answer 1

The correct option is D

d) molality

Explanation for correct answer

Correct answer is (d) molality

Molality

• Molality is defined as a measure of the number of moles of solute in the solution per kilogram of the solvent.
• The SI unit for molality is moles per kilogram of solvent.
• In the case of molality, moles are proportional to mass. At every temperature, mass is the same but with variations in temperature, molality will not change.

Hence, option d is correct.

Explanation for Incorrect answers

a) Molarity

• Molarity is defined as the measure of the number of moles of solute per litre of the solution. Since volume is dependent on temperature, therefore, option a is incorrect.

b) Normality

• Normality is defined as the measure of gram equivalent of solute, per litre of the solution. Since volume is dependent on temperature, therefore, option b is incorrect.

c) Formality

• Formality is a substance’s total concentration in solution without regard to its specific chemical form. The moles of solute and mass of solvent do not vary with temperature.

Hence, option c is incorrect.