Question

Reena bought a new bottle of pickle from the market. She tried to open the
metal cap but could not do so. She then took a bowl of hot water and immersed
the upper end of the bottle ( having the metal cap ) in it. She could easily open
the bottle now. Give a reason for this.

Answer 1

Answer:

expansion

Explanation:

when the bottle cap was soaked in hot water, it expanded and hence, opened it easily.

Answer 2

Answer:

Explanation:

Reena could do so because of the reversible change occurring in the metal cap, on the application of warm water. When Reena first tried, the metal cap was fit tightly on the bottle. On immersion in hot water, the metal expanded and the cap became loose, making it easy for her to open the cap.

This expansion of metal on heating is a reversible change, and the metal cap will come back to its original size on cooling.