First, let’s examine the differences between chemical and physical changes.
Chemical changes occur when a substance undergoes a reaction and a new substance is formed. Common indicators of a chemical change include gas formation, energy change (such as emission of heat or light), color change, or precipitate formation.
When a physical change occurs, the composition of the substance does not change. A common indicator of a physical change is phase change (ex. solid ice melts to liquid water).
Answer choices A, B, and C all represent chemical changes because these substances all undergo chemical change to form a new substance. Therefore, D is the correct answer because boiling water is a physical change as no new substance is formed during the reaction. The water undergoes phase change to evaporate and become a gas. When reaching a gaseous state, the water still has the same composition- it just takes on a different form.