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प्रश्न
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
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उत्तर
Aluminium is more reactive than iron. It reacts easily with oxygen in moist air and forms a layer of aluminium oxide on its surface. This aluminium oxide layer is very strong and does not allow the air to enter the metal for further reaction. This prevents further corrosion of aluminium. On the other hand, the formation of iron oxide layer by iron on reacting with moist air does not prevent the metal. It further allows the reaction between iron and moist air to continue and increases corrosion. Thus, aluminium is a highly resistive metal to corrosion and protects itself against corrosion as compared to iron when exposed to air.
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संबंधित प्रश्न
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Sound is produced
| A process of forming a thick oxide of aluminium when aluminium is exposed to air. This coat makes it resistant to corrosion. Resistance can be improved by making a layer of oxide thinker. In this technique, the aluminium article is the anode, and the electrolyte is sulphuric acid. The anode reaction results in the formation of a black-coloured film of aluminium oxide on the anode. By putting appropriate dyes in the electrolytic solution, both coloured surface with the decorative finish is achieved. Kitchen articles like anodised such as pressure cookers, pans and frames of sliding windows are applications of this technique. |
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