Answer: lowers the freezing point of water.
- A lowers the freezing point of water
- B raises the freezing point of water
- C increases the vapour pressure
- D acts as an oxidising agent
Correct answer: A. lowers the freezing point of water
Explanation: As a non-volatile solute it depresses the freezing point (and elevates the boiling point), acting as an antifreeze/coolant.
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.