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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
What is an alloy?
Tinning : Tin : : Galvanizing : _________
Write two methods of preventing the rusting of iron.
Why do we apply paint on iron articles?
Which metals do not corrode easily?
Give reasons:
Platinum, gold and silver are used to make jewellery.
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 the metal which is used for galvanising iron.
Fill in the following blank with suitable word:
The corrosion of copper produces a .............. coating of basic copper carbonate on its surface
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
What is the corrosion of iron known as?
What is meant by 'rusting of iron'? With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.
Give the constituents and one use of brass.
Name an alloy of copper. State its chemical composition and any one use.
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
No chemical reaction takes place when granules of a rusty-brown solid A are mixed with the powder of another solid B. However, when the mixture is heated, a reaction takes place between its components. One of the products C is a metal and settles down in the molten state while the other product D floats over it. It was observed that the reaction is highly exothermic.
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(b) What are the products C and D most likely to be?
(c) Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate the heat change which takes place.
(d) What is the special name of such a reaction? State one use of such a reaction.
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(a) Name the metals X and Y.
(b) Which of the two metals is more reactive : X or Y?
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(d) Name one ore or metal Y. Also write its chemical formula.
(e) Name one alloy of metal X and one alloy of metal Y.
Explain how the activity series accounts for each of the following:
tendency to corrosion
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Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
An iron article should be given a coat of paint
Give reason.
A wooden article should be polished.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
_______ is an alloy made from iron, carbon and chromium.
To prevent corrosion of iron and steel _______ method is used.
Find the odd one out and give its explanation.
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
Give preventive methods by giving examples of corrosion?
Give the equation for the formation of rust.
State two conditions necessary for rusting of iron.
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Identify the correct statement from the following:
Alloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents?
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
Gold plated ornaments is the example of ______.
