Page 197 - ICSE Chemistry 8

But if carbon is heated with limited supply of oxygen, it forms carbon monoxide.
2C + O 2CO + Heat
2
Carbon (Limited supply Carbon monoxide
of oxygen)
• When carbon is heated with hydrogen at 500°C and 250 atmospheric pressure, a mixture of
hydrocarbon containing methane, ethane, etc. is obtained.
• Carbon is a good reducing agent. It reduces oxides of metals placed below zinc in the metal ac vity
series to their corresponding metals.

ZnO + C Zn + CO
Zinc oxide Carbon Zinc Carbon monoxide

CuO + C Cu + CO
Copper(II) oxide Carbon Copper Carbon monoxide
Fe O 3 + 3C 2Fe + 3CO
2
Iron(III) oxide Carbon Iron Carbon monoxide
• Carbon reduces concentrated sulphuric acid and nitric acid to form sulphur dioxide and nitrogen
dioxide, respec vely. Carbon is oxidised to carbon dioxide in these reac ons.
C + 2H SO CO  + 2SO 2 + 2H O
2
2
4
2
Carbon Conc. sulphuric acid Carbon dioxide Sulphur dioxide Water
C + 4HNO CO  + 4NO 2 + 2H O
3
2
2
Carbon Conc. nitric acid Carbon dioxide Nitrogen dioxide Water
• Carbon in the form of wood charcoal reacts with sulphur vapours to form carbon disulphide when
heated strongly.
C + 2S CS 2
Carbon Sulphur Carbon disulphide
• Carbon reacts with calcium at a very high temperature (1000°C – 2800°C) to form its carbide.

heat
2C + Ca CaC 2
Carbon Calcium Calcium carbide

• When water in the form of steam is passed over red hot coke, it gets reduced to a mixture of
carbon monoxide and hydrogen which is also called water gas.
C + H O Co + H 2
2
Coke (red hot) Steam Water gas

• Carbon in the form of fi nely ground coke when heated strongly in the presence of electric arc,
reduces silicon dioxide to silicon carbide.
3C + SiO SiC + 2CO
2
Carbon Silicon dioxide Silicon carbide Carbon monoxide

ALLOTROPES OF CARBON

The various physical forms in which an element can exist are called allotropes of that element. Allotropes
have the same chemical proper es but diff erent physical proper es. The phenomenon of existence of an
element in more than one form in the same physical state is called allotropy.

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