Which of the following actions produces a chemical change?

The action of mixing vinegar and baking soda results in a chemical change because it produces a new substance through a chemical reaction. When vinegar, which contains acetic acid, is combined with baking soda, a base composed of sodium bicarbonate, they react with each other to form carbon dioxide gas, water, and sodium acetate. The evolution of gas and formation of new products indicates that a chemical change has occurred, as the original substances are transformed into entirely different materials.

In contrast, the other actions do not produce new substances that are chemically distinct from the original materials. Adding salt to hot water results in a physical change where the salt dissolves but remains sodium chloride. Boiling water involves the physical change of liquid water turning into steam, with no alteration to the chemical composition of H2O. Freezing juice is another physical change where the liquid undergoes a phase transition to become a solid but retains its original chemical identity.