Question

State the chemicals responsible for ozone layer destruction.

Answer 1

Chemicals responsible for the destruction of the ozone layer:

(1) Excessive use of CFCs:

CFCs enter the atmosphere because of their excessive use in solvents, aerosol sprays, propellants, refrigerants and blowing agents for plastic foams.

CFCs are decomposed by UV rays to highly reactive chlorine which is produced in the atomic form.

CF₂Cl_2(g) → CF₂Cl_(g) + Cl_(g)

This free radical [Cl] reacts with ozone, and chlorine monoxide is formed.

Cl_(g) + O_3(g) → ClO_(g) + O_2(g)

This causes depletion of ozone, and chlorine monoxide further reacts with atomic oxygen to produce more free radicals of chlorine.

ClO_(g) + O_(g)  → Cl_(g) + O_2(g)

Again this free radical [Cl] destroys ozone, and the process continues giving rise to large-scale ozone depletion.

(2)  The fuel of planes:

When the fuel of planes burns, a large quantity of nitric oxide and other gases is emitted in the atmosphere. Nitric oxide reacts with ozone to form nitrogen dioxide and nitrogen trioxide.

NO_(g) + O_3(g)  → NO_2(g) + O_2(g)

NO_2(g) + O_3(g) →  NO_3(g) + O_2(g)

This also causes depletion of ozone.