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प्रश्न
Corrosion of silver causes a black layer of _______.
पर्याय
Silver nitrate
silver oxide
silver sulphide
silver carbonate
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उत्तर
Corrosion of silver causes a black layer of silver sulphide.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Tinning : Tin : : Galvanizing : _________
Two methods by which rusting of iron can be prevented are ______ and ______.
Explain how painting of an iron gate prevents it from rusting.
Explain why rusting of iron objects is faster in coastal areas than in deserts.
What is anodising? Give its applications.
Fill in the following blank with suitable word:
The process of depositing a thin layer of zinc on iron articles is called .............
Give the constituents and one use of brass.
A metal X which is resistant to corrosion is produced by the electrolysis of its molten oxide whereas another metal Y which is also resistant to corrosion is produced by the reduction of its oxide with carbon. Metal X can be used in powder form in thermite welding whereas metal Y is used in making cathodes of ordinary dry cells.
(a) Name the metals X and Y.
(b) Which of the two metals is more reactive : X or Y?
(c) Name one ore or metal X. Also write its chemical formula.
(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.
Compare roasting and calcination.
Write scientific reasons.
Lemon or tamarind is used for cleaning copper vessels turned greenish.
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.
What are the adverse effects of corrosion?
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Write three methods of preventing rusting of iron.
Give reason.
An iron article should be given a coat of paint
Give reason.
Copper and brass utensils should be tinned.
Give a reason why rust turns moist red litmus blue.
_______ is an alloy made from iron, carbon and chromium.
To prevent corrosion of iron and steel _______ method is used.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
What is rust?
Give preventive methods by giving examples of corrosion?
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Amalgam is an alloy of ____________.
Copper objects lose their shine and form green coating of ____________.
Which among the following alloys contain mercury as one of its constituents?
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from sun.
- make it look beautiful.
- make it dust free.
Which of the above statement(s) is/are correct?
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.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
