Which of the following change cannot be reversed?
  1. Hardening of cement
  2. Freezing of ice cream
  3. Opening a door
  4. Melting of chocolate

AcademicChemistryNCERTClass 6

Correct Answer: (a) Hardening of cement 

Explanation: Hardening of cement is irreversible because once hardened, the cement cannot come back to its original shape.

Updated on 10-Oct-2022 13:20:12