This question has fascinated me since I came across it as a fact, but I wonder how it is possible? What makes ice get colder when salt (sodium chloride – NaCl) is added to it?
3 Answers
The salt dissolves into the liquid water in the ice and lowers its freezing point. As to why, Energy is required to snap the hydrogen bonds that hold the ice together.
Salt works to depress the freezing point of water so the water can become colder than 32 degrees Fahrenheit (zero degrees Celsius) before it turns to ice. … This salt water has a lower freezing point, so the temperature of the ice bath can get even colder, thus freezing the ice cream more quickly.