What happens to the freezing point of water when salt is added?

When salt is added to water, the freezing point of the water is lowered. This phenomenon occurs because the presence of salt disrupts the ability of water molecules to form a solid structure, which is necessary for freezing to occur.

In pure water, molecules can easily stabilize into a solid state (ice) at 0 degrees Celsius. However, when salt (sodium chloride) is dissolved in the water, the sodium and chloride ions interfere with the hydrogen bonds that hold the water molecules together in a solid form. As a result, the solution must reach a lower temperature than 0 degrees Celsius for the water to freeze.

This property of salt to lower the freezing point of water is utilized in various practical applications, such as de-icing roads in winter or making ice cream. Thus, adding salt effectively reduces the freezing point of water, which leads to the conclusion that the correct choice is indeed that it lowers.