Which one of the following is used as an antifreeze in cars?

The correct answer is Option (1) → Ethylene glycol

An antifreeze is a substance added to the water in a car radiator so that the water does not freeze in cold weather. It works through depression of freezing point: a dissolved solute lowers the freezing point of the solvent.

A good antifreeze must mix completely with water, must not evaporate from the hot radiator, and must be used in large amounts. Ethylene glycol (ethane-1,2-diol), \( \ce{HOCH2-CH2OH} \), meets all these needs: its two –OH groups form hydrogen bonds with water, so it is completely miscible, and its boiling point (470 K) is much higher than that of water.

So the antifreeze used in cars is ethylene glycol.

NCERT (2026-27 edition):
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