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प्रश्न
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
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उत्तर
(c) oxidation as well as combination
In the corrosion of iron metal, iron metal reacts with water and oxygen and forms hydrated oxide called rust.Addition of oxygen to the metal is a oxidation reaction.
4Fe + 3O2 + 2xH2O → 2Fe2O3.xH2O
Since iron metal combines with water and oxygen to corrode, it is also a combination reaction, in which iron metal, water and oxygen combine to form a single compound.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Why do we apply paint on iron articles?
Which metals do not corrode easily?
Explain why rusting of iron objects is faster in coastal areas than in deserts.
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
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.
(a) What could the solids A and B be?
(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.
(e) Name any two types of chemical reactions under which the above reaction can be classified.
Write scientific reasons.
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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 ..................................................................
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Electroplating
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
The table shown below gives information about four substances: A, B, C and D.
| SUBSTANCE | MELTING POINT (K) | ELECTRICAL CONDUCTIVITY | |
| SOLID | LIQUID/ AQUEOUS | ||
| A | 295 | Good | Good |
| B | 1210 | Poor | Good |
| C | 1890 | Poor | Good |
| D | 1160 | Poor | Poor |
Identify Ionic compounds from the above given substances.
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Gold plated ornaments is the example of ______.
