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प्रश्न
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.
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उत्तर
a. corrosion: Corrosion is a process where the water or the moisture on the surface of the metal oxidizes with the atmospheric oxygen.
b. Methods of prevention (any two each carry 1/2 mark) 1
1. Galvanizing 2. Anodization 3. Tinning
4. Electroplating 5. Alloying
c. Anodization
d. In this process cupper, aluminum are coated with a thin layer of their oxides by means of electrolysis. For this copper or aluminum article is used as anode. It obstructs the contact of the aluminum or copper with oxygen and water.
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संबंधित प्रश्न
Write two methods of preventing the rusting of iron.
Explain the terms Corrosion
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Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
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(a) oxidation as well as displacement
(b) reduction as well as combination
(c) oxidation as well as combination
(d) reduction as well as displacement
Name the metal which is used for galvanising iron.
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(b) copper
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Explain the following:
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Give an example of a chemical reaction for the following situation:
Sound is produced
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| 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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- Name the technique used to coat the aluminium articles.
In ______ process a layer of molten tin is deposited on metals.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
