Question

Which of the following is not a reversible change?

• A. Burning of incense stick and freezing water to form ice
• B. Drying of wet cloths and heating of metal
• C. Lighting of a matchstick and burning of a paper
• D. Folding and unfolding of paper and heating cold milk to prepare hot milk
  

Answer 1

The correct option is C Lighting of a matchstick and burning of a paper

Lighting of a matchstick and burning of a paper are not reversible changes because once the change takes place, the materials cannot come back to their original state. The remaining examples are reversible changes because the materials can return to their original state even after the change has taken place.