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प्रश्न
Why is an iron grill painted frequently?
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उत्तर
To prevent rusting of iron substances, they are painted frequently. Iron is a reactive metal and it starts corroding in the presence of air (oxygen) and water (or moisture). Iron reacts with oxygen present in the moist air and forms a brown flaky iron oxide (or rust) layer on its surface. This is called rusting. This rusting causes huge damage to iron substances by making them weak. Therefore, an iron grill is painted frequently to prevent corrosion.
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संबंधित प्रश्न
What is an alloy?
The chemical reaction involved in the corrosion of iron metal is that of:
(a) oxidation as well as displacement
(b) reduction as well as combination
(c) oxidation as well as combination
(d) reduction as well as displacement
What is corrosion?
Give the constituents and one use of brass.
What are the special properties of stainless steel?
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.
State under what conditions corrosion is faster ?
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 ..................................................................
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.
Give reason.
A wooden article should be polished.
_______ is an alloy made from iron, carbon and chromium.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Draw a neat labelled diagram.
Anodizing
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?
In ______ process a layer of molten tin is deposited on metals.
