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प्रश्न
Explain why, iron sheets are coated with zinc.
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उत्तर
Iron sheets are coated with zinc because zinc is a reactive metal which readily reacts with oxygen present in air to form a hard layer of zinc oxide. This layer is so hard that it prevents air and moisture from passing through it. Hence, moist air cannot come in contact with iron. This in turn prevents the rusting of iron.
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संबंधित प्रश्न
What is an alloy?
What are alloys?
Explain why rusting of iron objects is faster in coastal areas than in deserts.
The chemical reaction involved in the corrosion of iron metal is that of ______.
State two conditions for the rusting of iron.
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
Name any two metals which do not corrode easily.
Name a common metal which is highly resistant to corrosion.
Mention two uses of the following metals and non-metals
Iron
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.
Write the name.
An alloy of copper and tin-
What is 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 ____________.
The diagram shows the reaction between metal and dil. acid.
What is the reason for different behaviour of Mg in test tube B?
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.
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
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?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
