Question

Which of the following does not involve a chemical reaction?

Options

• digestion of food in our body.

• process of respiration.

• burning of candle wax when heated.

• melting of candle wax on heating.

Answer 1

Melting of candle wax on heating.

Explanation:

Melting of candle wax is a physical change, not a chemical reaction, because it only changes the state of the wax from solid to liquid without altering its chemical composition. No new chemical substances are formed, and the process can easily be reversed by cooling. In contrast, digestion, respiration, and burning all break down substances to create entirely new chemical products.