Why does putting salt in pasta water or antifreeze in a car radiator change the boiling/freezing point?
Both are colligative effects.
Both are colligative effects. A non-volatile solute raises the boiling point (elevation) and lowers the freezing point (depression) because it reduces the solvent's tendency to escape as vapour or lock into a solid. Antifreeze (ethylene glycol) in a radiator both stops the coolant freezing in winter and boiling over in summer — one additive, two colligative benefits.
Key point
A non-volatile solute raises boiling point and lowers freezing point, by particle count.
Common mistake
thinking salt makes water boil faster (it slightly raises the boiling point, not speeds heating).
Memory tip
dissolve something non-volatile → wider liquid range (higher BP, lower FP).
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