# Why is the freezing point of a solution, LOWER than that of the pure solvent?

The addition of a salt, any salt, to a solvent decreases the freezing point of that solvent by an amount proportional to the concentration of that salt in solution. This is a well-known colligative property. And thus addition of salt to water decreases the melting point below $0$ ""^@C. This is also observed when (in a cold North American climate), they salt the roads in winter to encourage the ice and frost to melt (with disastrous effects on the auto chassis!).