AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(B) Change in shape
The textbook lists change in state, change in colour, evolution of a gas, and change in temperature as indicators of a chemical reaction — change in shape is not listed.
Source: Chapter 1, Chemical Reactions and Equations (Activity 1.1–1.3 summary)
The NCERT text explicitly names four indicators: change in state, change in colour, evolution of gas, and change in temperature. "Change in shape" is a physical change only and is never mentioned as evidence of a chemical reaction. Examiners expect you to recall this specific list from the chapter.