Page 204 - Chemistry ICSE Class IX

192 ICSE Chemistry – 9
In the presence of air, NO gets oxidised to NO (nitrogen dioxide).
2
Nitrogen dioxide (NO ) in the presence of water forms nitric acid and
2
nitrous acid.
2NO (g) + H O(l) o HNO (aq) + HNO (aq)
2
2
2
3
nitrous acid nitric acid
What are the harmful effects of acid rain
Acid rain has the following harmful effects:
ƒ Acid rain promotes corrosion of metallic structures, such as bridges
and towers. The rusting of iron gets accelerated due to acid rain.
ƒ Acid rain damages the structures made of marble, cement and/or of
lime. Acid rain causes pitting of such structures and weakens them.
For example, structures, such as Taj Mahal, have great danger of
getting damaged by acid rain.
CaCO (s)+ H SO (aq) o CaSO 4 +CO (g)+ H O
2
2
4
2
3
limestone in acid rain sparingly
or marble soluble in water
CaCO (s) + 2HNO (aq) o Ca(NO )(aq)+ CO (g)+ H O
3
3
2
3
2
limestone in acid rain highly
or marble soluble in water
ƒ Acid rain harms the aquatic life of water bodies. It kills sh and other
animals living in water.
ƒ Acid rain damages the nutrition level of plants and damages the
leaves and roots of plants and trees.
ƒ Acid rain destroys many soil nutrients and causes loss of soil fertility.
ƒ Acid rain having higher concentration of sulphurous and sulphuric
acids may cause respiratory problems and injure lung tissues.
The Taj Mahal and acid rain

dŚĞ dĂũ DĂŚĂů ůŽĐĂƚĞĚ Ăƚ ŐƌĂ ŝƐ ƐƵƌƌŽƵŶĚĞĚ ďLJ Ă ůĂƌŐĞ ŶƵŵďĞƌ ŽĨ ŝŶĚƵƐƚƌŝĞƐ ǁŚŝĐŚ ƌĞůĞĂƐĞ ůĂƌŐĞ
ƋƵĂŶƟƟĞƐ ŽĨ ƚŚĞ ŽdžŝĚĞƐ ŽĨ ƐƵůƉŚƵƌ ĂŶĚ ŶŝƚƌŽŐĞŶ͘ dŚĞ ƉĞƚƌŽůĞƵŵ ƌĞĮŶĞƌLJ Ăƚ DĂƚŚƵƌĂ ŝƐ ĂŶŽƚŚĞƌ ďŝŐ
ƐŽƵƌĐĞ ŽĨ ƐƵůƉŚƵƌ ŽdžŝĚĞƐ͘ dŚĞ ĂĐŝĚŝĐ ŐĂƐĞƐ ůŝŬĞ ^K ͕^K ͕ĂŶĚ EK ŐŝǀĞ ƌŝƐĞ ƚŽ ĂĐŝĚ ƌĂŝŶ ĐŽŶƚĂŝŶŝŶŐ
Ϯ
Ϯ
ϯ
H SO ͕, SO ĂŶĚ ,EK ͘ Ɛ Ă ƌĞƐƵůƚ͕ ƚŚĞ ŵĂƌďůĞ ; Ă K Ϳ ŽĨ ƚŚĞ dĂũ DĂŚĂů ǁŝůů ŐĞƚ ĐŽƌƌŽĚĞĚ ĂŶĚ
ϯ
ϯ
Ϯ
ϰ
ϯ
Ϯ
ůŽƐĞ ŝƚƐ ůƵƐƚƌĞ͘
DĂŶLJ ƉƌĞĐĂƵƟŽŶĂƌLJ ƐƚĞƉƐ ŚĂǀĞ ďĞĞŶ ƚĂŬĞŶ ƚŽ ƉƌĞǀĞŶƚ ƐƵĐŚ ĚĂŵĂŐĞ ƚŽ ƚŚĞ dĂũ DĂŚĂů͘
How can the harmful effects of acid rain be reduced
The harmful effects of acid can be reduced by reducing the emission of
the oxides of sulphur and nitrogen. This can be done by following the
suggestions given below:
ƒ By reducing the use of fossil fuels.
The use of fossil fuels can be reduced by
Š Using low sulphur coal and petrol.
Š Using lesser electricity. Replace lament bulbs by CFLs.
Š Using automobiles only for longer distances. For shorter distances,
either walk down or use bicycle.
Š Using alternative sources of energy, viz. solar energy, wind energy,
hydroenergy, etc.
Š Using scrubbers in industries to remove oxides of sulphur from
the waste gases before releasing these into the atmosphere.