How many of the following ways of expressing the concentration of a solution are independent of temperature?
Mass percentage, Molarity, Parts per million (by mass), Mole fraction, Molality
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 4
The volume of a solution changes with temperature, but its mass does not. So a concentration term built only on masses or moles is independent of temperature, while a term that uses the volume of the solution changes with temperature.
Independent of temperature:
Mass percentage (mass per mass of solution)
Parts per million (by mass) (parts per million parts by mass)
Mole fraction (a ratio of moles)
Molality (moles per kilogram of solvent)
Depends on temperature:
Molarity — moles of solute per litre of solution, and the volume changes with temperature.
Independent of temperature: 4 terms.
NCERT (2026-27 edition):
1.2 Expressing Concentration of Solutions – “Each method of expressing concentration of the solutions has its own merits and demerits. Mass %, ppm, mole fraction and molality are independent of temperature, whereas molarity is a function of temperature. This is because volume depends on temperature and the mass does not.”