Answer: Lower concentration to higher.
- A Higher concentration to lower
- B Lower concentration to higher
- C Higher pressure to lower
- D Solid to liquid
Correct answer: B. Lower concentration to higher
Explanation: Solvent flows from dilute (lower solute concentration) to concentrated solution through a semi-permeable membrane.
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.