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प्रश्न
State the chemicals responsible for ozone layer destruction.
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उत्तर
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.
CF2Cl2(g) → CF2Cl(g) + Cl(g)
This free radical [Cl] reacts with ozone, and chlorine monoxide is formed.
Cl(g) + O3(g) → ClO(g) + O2(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) + O2(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) + O3(g) → NO2(g) + O2(g)
NO2(g) + O3(g) → NO3(g) + O2(g)
This also causes depletion of ozone.
संबंधित प्रश्न
How does ozone affect any ecosystem?
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
What is ozone?
The depletion of ozone layer in the upper atmosphere is mainly due to the emission of :
(a) unburnt hydrocarbons
(b) chlorofluorocarbons
(c) greenhouse gases
(d) ultraviolet radiations
O2 is converted into O3 by the action of :
(a) infrared radiations
(b) ultraviolet radiations
(c) gamma radiations
(d) cosmic radiations
Match the items in column I with the closely related ones in column II.
| Column I | Column II | ||
| (i) | Chlorofluorocarbons (CFCs) | (a) | Global warming |
| (ii) | Fly ash | (b) | Biodegradable |
| (iii) | Cow dung | (c) | Nuclear radiation pollutant |
| (iv) | CO2 and methane | (d) | Acid rain |
| (v) | Sulphur dioxide | (e) | Industrial waste |
| (vi) | Iodine-131 | (f) | Ozone depletion |
Number of Oxygen atom in Ozone.
Give Technical Terms:
The chemicals leading to the formation of ozone holes.
Bad ozone is present in ______
Gas A, found in the upper layers of the atmosphere, is a deadly poison but is essential for all living beings. The amount of this gas started declining sharply in the 1980s.
- Identify Gas A. How is it formed at higher levels of the atmosphere?
- Why is it essential for all living beings? State the cause for the depletion of this gas.
