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प्रश्न
What is anodising? Give its applications.
What is meant by 'anodising'? Why is it done?
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उत्तर १
Anodising is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. The process is called anodising because the part to be treated forms the anode electrode of an electrical circuit.
It is very useful in preventing the metal from corrosion. It is also useful in architectural finishing.
उत्तर २
Anodising is a method that involves the formation of tough layer of aluminium oxide on aluminium substances by making it anode in the electrolysis of sulphuric acid. Generally, the formation of aluminium oxide layer on aluminium protects it from corroding further. However, if this oxide layer on aluminium is made thicker (by anodising), it will become a strong coating and will prevent corrosion to the maximum.
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संबंधित प्रश्न
Tinning : Tin : : Galvanizing : _________
Two methods by which rusting of iron can be prevented are ______ and ______.
What type of chemical reaction is involved in the corrosion of iron?
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
State two conditions for the rusting of iron.
Explain why, though aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
Give the constituents of brass.
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
What is corrosion? What are necessary conditions for corrosion?
Corrosion can be an advantage in some case.Explain ?
Write scientific reasons.
Lemon or tamarind is used for cleaning copper vessels turned greenish.
Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
Reaction on anode region :
`F_e(s) → Fe^(2+) (aq) +2e^-`
Reaction on anode region :
`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `
When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.
`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `
A way to prevent rusting ..................................................................
Write three methods of preventing rusting of iron.
Give reason.
An iron article should be given a coat of paint
Give reason.
A wooden article should be polished.
State two conditions necessary for rusting of iron.
Copper objects lose their shine and form green coating of ____________.
Give an example of a chemical reaction for the following situation:
Sound is produced
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
