Which one of the following processes involve chemical reactions?

(A) Storing of oxygen gas under pressure in a gas cylinder

(B) Liquefaction of air

(C) Keeping petrol in a china dish in the open

(D) Heating copper wire in presence of air at high temperature



Chemical Change vs Physical Change-01.jpg

A physical change is the one in which the chemical properties of a substance do not change

No chemical change is observed when we store oxygen gas under pressure, or during liquefaction of air or when petrol is kept open in a china dish.


However, when we heat a copper wire in the presence of air, copper oxide is formed .

The reaction is as follows:

Reaction of Copper with Oxygen - Teachoo.jpg

So, the correct option is (d) heating copper wire in presence of air at a high temp

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo