(a) Why is change in colour of a cut apple slice on being kept in air is a chemical change?

(b) State one instance where water undergoes a physical change and one in which it undergoes a chemical change.

Asked by Topperlearning User | 8th May, 2014, 09:33: AM

Expert Answer:

(a) When slice of a cut apple is exposed to air for some time, it acquires a brown colour due to the formation of new substances by the action of oxygen present in the air. Hence, the change in colour of the cut apple slice is a chemical change.

(b) Physical change: Freezing of water into ice/boiling of water to form steam.

     Chemical change: Electrolysis of water to form hydrogen and oxygen.

Answered by  | 8th May, 2014, 11:33: AM