What occurs when salt is added to water and the mixture is frozen?

When salt is added to water and the mixture is frozen, freezing point depression occurs. This phenomenon is a colligative property of solutions, where the presence of a solute, such as salt, lowers the freezing point of the solvent, which in this case is water.

The addition of salt disrupts the formation of the regular crystalline structure that ice requires. As salt ions interfere with the hydrogen bonding between water molecules, it takes a lower temperature for the water molecules to achieve the energy state necessary to freeze. This is why brine (saltwater) can remain liquid at temperatures where pure water would typically freeze.

This principle is commonly applied in various practical situations, such as in the melting of ice on roads during winter or in making ice cream, where salt is added to lower the freezing point and achieve a smoother texture. In contrast, options regarding gas formation, evaporation, or no change do not accurately reflect the physical principles involved in the freezing process of a saline solution.