Question

Ozone depletion is occurring widely in the stratosphere, it leads to ozone hole caused mainly due to
(a) Ethylene
(b) Methane
(c) Chlorofluorocarbons (CFCs)
(d) Carbon dioxide

Answer 1

Hint: The main culprit in causing the hole in the ozone layer is a fully halogenated paraffin hydrocarbon and is widely used as a refrigerant and solvent.

Complete answer:
The depletion of the ozone layer in the stratosphere is caused by the presence of chlorofluorocarbons in the atmosphere. The CFCs cause the breaking of the ozone molecules, resulting in the formation of the oxygen radical and ${ O }_{ 2 }$. The depletion of the ozone layer leads to the formation of an ozone hole due to which harmful UV radiation from the sun penetrates the Earth's atmosphere.
The primary causes of ozone depletion are referred to as ozone-depleting substances (ODS). These are specially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents such as chlorofluorocarbons (CFCs), HCFCs, and halons.

So, the correct answer is ‘CFCs Chlorofluorocarbons’.

Note: -Ethylene (IUPAC name: ethene) is the simplest alkene that has the formula $ { C }_{ 2 }{ H }_{ 4 }$. It is a colorless flammable gas and has a faint "sweet and musky" odor when pure.
-Methane and carbon dioxide are greenhouse gasses.
-CFCs are transported into the stratosphere by turbulent mixing after being emitted from the surface. Turbulent mixing means mixing much faster than the molecules can settle.
-They release halogen atoms through photodissociation in the stratosphere, which catalyze the breakdown of ozone ${ O }_{ 3 }$ into oxygen ${ O }_{ 2 }$.
-Depletion is observed to increase as emissions of halocarbons increase.