Page 202 - Chemistry ICSE Class IX

190 ICSE Chemistry – 9
SO (g) + H O(v) o H SO (aq)
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/Ŷ ĞĐĞŵďĞƌ ϭϵϱϮ͕ ϯϮϬϬ ƉĞŽƉůĞ ĚŝĞĚ Sulphur dioxide 2 droplets of sulphurous acid
ĚƵĞ ƚŽ ĐŚĞŵŝĐĂů ƐŵŽŐ ǁŚĞŶ ƚŚĞ ĐŝƚLJ
ŽĨ >ŽŶĚŽŶ ƌĞŵĂŝŶĞĚ ĐŽǀĞƌĞĚ ǁŝƚŚ The droplets of H SO (aq) get condensed on the smoke/dust particles
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ƚŚĞ ĐŚĞŵŝĐĂů ƐŵŽŐ ĨŽƌ ĮǀĞ ĚĂLJƐ͘ and form a colloidal dispersion called chemical smog.
What is the photochemical smog
Photochemical smog occurs in big cities with warm, dry and sunny climate.
Photochemical smog is a brown hazy fumes. The photochemical smog is
produced by the action of sunlight on nitrogen oxides and hydrocarbons.
A highly toxic compound called peroxyacetyl nitrate (PAN) mixes with fog
dŚĞ ĨĂŵŽƵƐ >ŽƐ ŶŐĞůĞƐ ;h^ Ϳ ƐŵŽŐ to form photochemical smog.
ǁĂƐ Ă ƉŚŽƚŽĐŚĞŵŝĐĂů ƐŵŽŐ͘
Fog + Smoke/Dust + PAN o Photochemical smog

What are the harmful effects of smog
W E ŝƐ Ă ŚŝŐŚůLJ ƚŽdžŝĐ ĐŽŵƉŽƵŶĚ͘ /ƚ ƒ Chemical smog causes respiratory problems.
ŝƐ ŚĂƌŵĨƵů ƚŽ ŚƵŵĂŶƐ ĞǀĞŶ Ăƚ Ă ǀĞƌLJ ƒ Photochemical smog decreases visibility, causes eye irritation and
ůŽǁ ĐŽŶĐĞŶƚƌĂƟŽŶ |രϬ͘ϭ ƉƉŵ͘
damages plants. Rubber when exposed to photochemical smog
become in exible and brittle.

How can the smog formation be controlled
The smog formation can be controlled by
ƒ Minimising the use of petrol/diesel based automobiles
ƒ Use of low sulphur fossil fuels
ƒ Installation of catalytic converters in automobiles.

How can atmospheric pollution be controlled
The atmospheric pollution (or air pollution) can be controlled by the
following measures:
ƒ By improving the quality of fuels used in automobiles and using
catalytic converter in them. Use of CNG or LNG in automobiles
should be encouraged.
ƒ By replacing wood, coal, and kerosene by LPG for domestic use.
ƒ By reducing the use of fossil fuels.
ƒ By using solar cookers, solar heaters and windmills.
ƒ By using lters or electric precipitator in industrial chimneys.
ƒ Do not burn dry leaves, branches of trees, and garbage in the open.
ƒ Reduce the use of aerosols.

CNG Filling station ƒ Do not smoke.

ASSIGNMENT 3

Harmful effects of carbon monoxide, Control of carbon monoxide pollution,
Smog, Control of atmospheric pollution

ϭ͘ tŚLJ ŝƐ K ĐŽŶƐŝĚĞƌĞĚ Ă ĚĂŶŐĞƌŽƵƐ Ăŝƌ ƉŽůůƵƚĂŶƚ͍
Ϯ͘ 'ŝǀĞ ƚǁŽ ƐƵŐŐĞƐƟŽŶƐ ƚŽ ĐŽŶƚƌŽů ƚŚĞ ƉŽůůƵƟŽŶ ĐĂƵƐĞĚ ďLJ ĐĂƌďŽŶ ŵŽŶŽdžŝĚĞ͘
ϯ͘ EĂŵĞ ƚŚĞ ĐĂƚĂůLJƟĐ ŵĂƚĞƌŝĂů ƵƐĞĚ ŝŶ ĐĂƚĂůLJƟĐ ĐŽŶǀĞƌƚĞƌ ĮƩĞĚ ŝŶ ĂƵƚŽŵŽďŝůĞƐ͘
ϰ͘ tŚĂƚ ŝƐ ƚŚĞ ĐĂƵƐĞ ŽĨ ĐŚĞŵŝĐĂů ƐŵŽŐ͍ ,Žǁ ĚŽĞƐ ŝƚ ĂīĞĐƚ ƵƐ͍
ϱ͘ EĂŵĞ ƚŚĞ ƚŽdžŝĐ ƐƵďƐƚĂŶĐĞ ƚŚĂƚ ƚŽŐĞƚŚĞƌ ǁŝƚŚ ƐŵŽŬĞ͕ ĚƵƐƚ ĂŶĚ ĨŽŐ ƉƌŽĚƵĐĞƐ ƉŚŽƚŽĐŚĞŵŝĐĂů ƐŵŽŐ͘
ϲ͘ tŚLJ ŝƐ ƚŚĞ ƵƐĞ ŽĨ ƐŽůĂƌ ĐŽŽŬĞƌƐ͕ ƐŽůĂƌ ŚĞĂƚĞƌƐ ĂŶĚ ǁŝŶĚŵŝůůƐ ƌĞĐŽŵŵĞŶĚĞĚ ŝŶ ƉƌĞĨĞƌĞŶĐĞ ƚŽ ĐŽĂů Žƌ ŬĞƌŽƐĞŶĞ͍