Question

37. Which of the following processes is/are chemical changes?

1. Extracting iron from iron ore

2. Explosion of a firework

3. Stretching a rubber band

Options:

• A. a. 1 only
• B. b. 1 and 2 only
• C. c. 3 only
• D. d. 1 and 3 only

Answer 1

The correct option is B

b. 1 and 2 only

Answer-b

A change in which one or more new substances are formed is called a chemical change. A chemicalchange is also called a chemical reaction. For eg - Explosion of a firework

A change in which a substance undergoes a change in its physical properties is called a physical change.

A physical change is generally reversible. In such a change no new substance is formed. For eg. Stretching rubber band represents a physical change.