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

When salt is added to water, the freezing point of that water decreases. This phenomenon is known as freezing point depression. Salt (sodium chloride) dissociates into its component ions when dissolved in water, which disrupts the formation of the ice lattice structure that occurs during freezing. As a result, a lower temperature is required to achieve the same level of molecular organization necessary for the water molecules to solidify into ice.

The degree to which the freezing point is lowered depends on the concentration of salt in the solution. For example, the presence of salt in ice water is why salted roads are less prone to freezing in winter; the salt helps keep the temperature below the normal freezing point of pure water. This principle is utilized in various applications including culinary practices and road maintenance during winter months. Understanding this concept is crucial, particularly in scientific contexts related to chemistry and environmental engineering, as well as practical applications in everyday life.