Page 205 - ICSE Chemistry 8

Activity 9.4

Aim: To show that charcoal is a good reducing agent
Materials required: Two test tubes, some black copper(II)
copper(II) oxide
oxide, some powdered charcoal, some palladium + charcoal
chloride solu on, a burner, a delivery tube
Procedure

• Set the apparatus as shown in the fi gure.
palladium
• Take some black copper(II) oxide in a test tube. chloride
solution
Heat it with powdered charcoal.

• Pass the gas evolved through palladium chloride
solu on.
Observa on: The palladium chloride solu on turns pink with the evolu on of a colourless gas. Reddish
par cles of copper metal are formed in the test tube.
Conclusion: This shows that charcoal consis ng of carbon reduces copper(II) oxide to copper metal and
carbon monoxide gas is evolved.
CuO + C Cu + CO
Copper(II) oxide Powdered Copper Carbon monoxide
charcoal (reddish) (colourless gas)

Bone or Animal Charcoal

Bone or animal charcoal is a granular black substance
that contains only 10% carbon and a high percentage of
impuri es like calcium phosphate and calcium carbonate.
It is obtained by fi rst boiling bones in water to remove
fa y substances and then subjec ng them to destruc ve
dis lla on. Bone charcoal is a good decolourising agent as
Fig. 9.8: Bone charcoal
it has the property of adsorbing coloured impuri es from
a solu on.

Uses of Bone or Animal Charcoal
Thinking Fountain
• It is extensively used to decolourise cane sugar solu on. Why is bone charcoal used as
a decolourising agent?
• It is used to remove fl uoride from water.
• It is used to manufacture a large number of phosphorus compounds.

• Calcium phosphate present in bone charcoal dissolves on trea ng it with hydrochloric acid. From
this solu on, carbon is fi ltered and is called bone black or ivory black. Ivory black is used as a black
pigment in ar s c pain ng because it is the deepest available black colour.
• It is used to fi lter aquarium water.
• It is used to refi ne crude oil for the produc on of petroleum jelly.

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