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🧪 Chemistry  ·  Solutions  ·  NEET & JEE

Compared with the pure solvent, the freezing point of a solution is:

Answer: lower.

  • A higher
  • B lower
  • C the same
  • D doubled

Correct answer: B. lower

Explanation: A solute depresses the freezing point, so the solution freezes below the pure solvent’s freezing point.

Vapour Pressure: Pure Solvent vs SolutionTVapour PPure solventSolution (lower VP)ΔTfTf(soln)Tf(pure)Dissolved solute lowers vapour pressure at every temperature, shifting Tf down and Tb up

Adding a non-volatile solute lowers the solvent's vapour pressure at every temperature, which is the root cause behind all four colligative properties: it shifts the freezing point down and the boiling point up.

Concept context

Learn how substances dissolve and form mixtures. Covers concentration terms, colligative properties (boiling point elevation, freezing point depression, osmotic pressure), and ideal vs non-ideal solution behaviour.

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