Page 161 - ICSE Chemistry 8

• Hydrogen is used to produce hydrogen chloride gas.
• Hydrogen is seen as an alternate source of energy for the future. It can even replace hydrocarbons
as it forms water rather than harmful gases on burning. It is a pollu on-free fuel (clean fuel).

Coal Gas
A gaseous mixture mainly consis ng of hydrogen, methane and carbon monoxide formed by the destruc ve
dis lla on of coal.
Water Gas
A gaseous mixture of carbon monoxide and hydrogen formed by passing steam over red-hot coke.

Metallurgy
A branch of science that deals with the proper es of metals and the process of separa ng them from other
ma er in the ore.

Take a Break!

Write/Choose the correct answer.
1. Hydrogen is almost insoluble in water. (True/False)
2. Hydrogen burns in air with a ________________ fl ame.

3. Hydrogen is non-combus ble in air but it supports combus on. (True/False)
4. The reac on of hydrogen with oxygen is highly ______________.

5. What happens when hydrogen is passed through molten sulphur?
6. Hydrogen is used as a ________________ agent in metallurgy to extract pure metals from their
________________.

Terms to Know

Displacement reac ons: Reac ons in which hydrogen gets displaced from its compounds like water, acids
and alkalis by more reac ve metals
Ac vity series of metals: A list of metals arranged in order of their decreasing reac vity
Electrolysis: A process in which acidulated water dissociates into hydrogen and oxygen on
passage of electric current
Cataly c hydrogena on
of oils: A process in which liquid vegetable oils are treated with hydrogen under pressure in
the presence of fi nely divided nickel, palladium or pla num to make solid vanaspa
ghee

Oxida on: A process of adding oxygen to an element or compound
Reduc on: A process of removing oxygen by adding hydrogen to an element or compound
Water gas: A mixture of carbon monoxide and hydrogen

Hydrocarbons: Compounds formed when hydrogen combines with carbon
Redox reac on: A reac on in which both oxida on and reduc on occur simultaneously

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