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प्रश्न
Give the equation for the formation of rust.
उत्तर
4Fe + 3O2 + xH2O → 2Fe2O3. xH2O (Rust).
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संबंधित प्रश्न
What is corrosion?
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
What is done to prevent corrosion of metals?
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Give preventive methods by giving examples of corrosion?
Copper objects lose their shine and form green coating of ____________.
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
| 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. |
- Name the anode and electrolyte used in this technique.
- How can we make aluminium articles made resistant to corrosion?
- Name the technique used to coat the aluminium articles.
