Which of the following concentration units of a solution is temperature-dependent?
A{'text': 'Molality', 'label': 'A'}
B{'text': 'Mass percentage', 'label': 'B'}
C{'text': 'Molarity', 'label': 'C'}
D{'text': 'Mole fraction', 'label': 'D'}
Answer & Solution
Correct answer: C. {'text': 'Molarity', 'label': 'C'}
1. Molality is moles of solute per kg of solvent — mass does not change with temperature.
2. Mass percentage is w/w — mass ratio, temperature independent.
3. Mole fraction is a ratio of moles — no volume, so temperature independent.
4. Molarity is moles per LITRE of solution; volume depends on temperature, so molarity varies with T.
_Source: NCERT Class 12 Chemistry, Unit 1 "Solutions", §1.2_
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