Q4 of 29 Page 162

Give scientific explanation

The aluminium article is used as an anode in the anodising process.

Dilute acid is taken in the electrolytic cell and

the aluminium article is dipped in it as the anode. When an electric current is passed hydrogen gas is released at the cathode and oxygen gas at the anode. A reaction with oxygen occurs and a layer of hydrated aluminium oxide is formed on the anode, i.e. the iron article..This layer can be made attractive by adding colour in the cell during electrolysis.


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