Question

Which
of
following
changes
cannot
be
reversed?


a. Hardening
of
cement







c.
Freezing
of
ice
cream

b. Opening
of
door















d.
melting
of
chocolate​

Answer 1

Answer:

a. Hardening of cement

hardening of cement is irreversible

Answer 2

Answer:

A. hardening of cement

Explanation:

It is because all others are physical changes and only hardening of cement can not be reversed....

only a option is a chemical change...

I hope it will help you out.