Question

How does the freezing process of ice cream occur?

What happens to ice when salt is added?

Answer 1

NaCl added to ice lowers the freezing point of ice to below zero C, melting the ice takes energy, the energy must come form someplace; it comes from the water/ice mixture. The result is that the temperature of the ice/salt/water mixture is below zero. It can be MUCH lower than zero; enough to freeze the ice cream mixture.