Question

which of the following changes cannot bereversed? ​

Answer 1

Changes that cannot be reversed are called irreversible changes. Some examples are as follows : Milk into curd. Burning of wood.

Answer 2

A reversible change is a physical change that can be undone.

A final substance can be converted back to the original substance without creating any new material.

An irreversible change is a permanent change that cannot be undone.

A. Hardening of cement is an irreversible change as we cannot reverse back to the original cement powder form once the cement hardens.

B. Freezing of ice-cream is reversible change as it can be reversed back by heating and it will convert to original form.

C. Opening of a door is reversible change as it can be reversed simply by closing the door

D. Melting of chocolate is reversible change as it can be reversed by cooling the chocolate to its original form.

Option A is the correct answer.