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प्रश्न
What is meant by galvanisation? Why is it done?
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उत्तर
Galvanisation is a process wherein a thin layer of zinc metal gets deposited on iron objects. This is done to prevent rusting of iron by protecting it to come in contact with air and moisture. Zinc metal, being more reactive, reacts with air to form hard layer of zinc oxide, which prevents air from passing through it.
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संबंधित प्रश्न
Give reasons:
Platinum, gold and silver are used to make jewellery.
What is anodising? Give its applications.
Name any two metals which do not corrode easily.
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
Answer the following question.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.
Find the odd man out:
Write three methods of preventing rusting of iron.
What is ‘rusting’?
Answer the following question.
List two properties of alloys.
Give reason for the following:
A suspension of rust is basic in nature.
_______ forms a green colour in the water.
Find the odd one out and give its explanation.
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Gold plated ornaments is the example of ______.
| 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.
In ______ process a layer of molten tin is deposited on metals.
