Page 158 - ICSE Chemistry 8

Activity 7.3

Aim: To show the forma on of hydrogen chloride gas
chlorine gas
Materials required: A jar fi lled with hydrogen gas, a jar fi lled with
chlorines gas
Procedure

• Take two jars. Fill a jar with hydrogen gas and the other with
chlorine gas.
• Invert the jar fi lled with chlorine over the jar fi lled with hydrogen
gas.

• Remove the lids of both jars to mix the two gases.
hydrogen gas
• Expose the two jars to sunlight.
Observa on: The greenish yellow colour of chlorine gas disappears
and a colourless gas is formed.

• Now bring a glass rod dipped in ammonia solu on near the
mouth of the gas jar.
Observa on: Dense white fumes of ammonium chloride are produced.
Conclusion: This shows the forma on of hydrogen chloride gas when hydrogen gas reacts with chlorine in
the presence of diff used sunlight.

• Reac on with nitrogen: Hydrogen does not combine with nitrogen under ordinary condi ons. In
the presence of fi nely divided iron dust which acts as a catalyst and at 450°C temperature and
200 atmospheric pressure, hydrogen reacts with nitrogen in the ra o 3:1 by volume to produce
ammonia gas. Molybdenum acts as a promotor of the reac on. This reac on is reversible and
exothermic, and is known as the Haber’s process.
Iron
N (g) + 3H (g) 2NH (g)  + Heat
2
2
3
Nitrogen Hydrogen 400°C, 200 atm Ammonia
• Reac on with sulphur: When hydrogen gas is passed through molten sulphur, hydrogen sulphide
gas is formed which gives a ro en egg smell.

H (g) + S(s) H S(g) 
2
2
Hydrogen Molten sulphur Hydrogen sulphide
• Reac on with carbon dioxide: When hydrogen combines with carbon dioxide at a temperature of
300–400°C under high pressure in the presence of nickel ac ng as a catalyst, methane and water
are produced.
CO (g) + 4H (g) CH (g) + H O(l) + Energy
2
4
2
2
Carbon dioxide Hydrogen Methane Water
This reac on is known as Saba er reac on. The requirement of water for astronauts inside the
Interna onal Space Sta on is fulfi lled using this reac on.

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