Question

An ozone depleting chemical, which is used in fire-extinguishers is _____.
A. Nitrogen oxide
B. Methyl bromide
C. Halon
D. Chlorofluorocarbon

Answer 1

Hint: Ozone depletion occurs due to presence of harmful gases in the atmosphere. Dissociation of ozone molecules into oxygen molecules leads to its depletion because oxygen molecules do not act as protective layers. CFC is released from refrigerators. Nitrogen oxide is released from vehicles while halon is present in fire extinguishers.

Complete answer:
Ozone is the protective layer of the earth. It is formed by the fusion of a free oxygen atom with an oxygen molecule. The general formula of ozone is ${O_3}$. Depletion of ozone occurs due to accumulation of harmful gases in the atmosphere. Gases such as chlorofluorocarbons, halon, carbon tetrachloride, hydrobromofluorocarbons, methyl bromide, nitrogen oxide, etc. all these gases accumulate in the stratosphere and when exposed to U.V rays. They dissociate into chlorine and bromine and they react with ozone to form diatomic oxygen and molecular oxygen.
CFC and HCFCs are released from refrigerators and air conditioners. Carbon dioxide is produced from factories, vehicles, etc. it can cause greenhouse effects and cause ozone depletion. CFC has an ozone depletion potential of 1.0. Due to the presence of these gases in the atmosphere, the temperature of the atmosphere increases and global warming can occur.
 Methyl bromide used for fumigation of soil, structures and goods to be imported or exported. Nitrogen oxide is released from the vehicular exhausts and industrial wastes.
HCFCs and halons used in fire extinguishers can cause ozone depletion. Bromotrifluoromethane (halon-1301) has a higher ozone depletion potential that is 10.0.
From the above information we can say that halon is the ozone depleting chemical used in fire extinguishers.

Therefore, the correct answer is option C.

Note: For the protection of ozone layer an act was made in 1989 named ozone protection and synthetic greenhouse gas management act. It controls the manufacture, import or export, use and disposal of ozone depleting substances. Some of the ozone depletion substances are still used in quarantine and safety applications as there is no suitable alternative.