Question

Depletion of ozone is mainly due to:
A. Chlorofluorocarbon compounds
B. Carbon monoxide
C. Methane
D. Pesticides

Answer 1

Hint: The ozone protects the earth from the harmful radiation of the sun by absorbing it. It can absorb maximum 99% of radiation but on reacting with the halogen atom released by the ozone depleting substances it can deplete the ozone layer.

Complete step by step answer:
Ozone is a layer present in earth stratosphere which mainly contains ozone and protects the earth from the harmful radiation of ultraviolet rays. It is found in the lower portion of the earth atmosphere. The ozone layer can absorb 97-99% of harmful radiation coming from the sun. In the absence of ozone layer many lives may suffer severe skin diseases including skin cancer.
The ozone layer depletion is the slow thinning of the ozone layer present in the earth’s atmosphere due to the release of harmful chemical compounds by industries, transport vehicles used by humans. The chemical compound depleting the ozone layer contains gaseous bromine and chlorine elements.
Some chemical compounds release chlorine and bromine gas on coming in contact with ultraviolet radiation which then leads to ozone layer depletion. These compounds are called Ozone depleting substances.
The chlorine containing compounds are Chlorofluorocarbons which are the main reason of ozone layer depletion. The chlorofluorocarbons are released by various solvents, refrigerators, and air-conditioners.
The containing chlorofluorocarbons are broken down in the stratosphere by the ultraviolet rays and release chlorine. The chlorine reacts with the ozone and depletes it.
Thus, depletion of ozone is mainly due to Chlorofluorocarbon compounds.

Therefore, the correct option is A.

Note: The other compounds containing chlorine which cause depletion of ozone layer are carbon tetrachloride, methyl chloride, hydrochlorofluorocarbons and the compounds containing bromine are methyl bromide, , hydrobromofluorocarbons.