JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Solutions

The quantity which changes with temperature is:

(A)Molarity✓ Correct
(B)Mass percentage
(C)Molality
(D)Mole fraction

Answer: (A)

Solution

Molarity is defined as moles of solute per litre of solution:

M = \frac{n _{so l u t e}}{V _{so l u t i o n}}

. Since the volume of a liquid solution expands on heating and contracts on cooling, molarity changes with temperature even though the amount of solute is fixed.

Mass percentage, molality and mole fraction are all defined in terms of masses or moles of solute and solvent — quantities that do not change with temperature — so these three remain constant regardless of temperature.

JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Single correct option

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