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प्रश्न
Observe the following picture and answer the following questions:
- What is rust?
- Write the chemical formula of rust.
- Write the reaction of oxidation of iron at the anode.
- Write the reaction of oxidation of iron at the cathode.
- What is corrosion?
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उत्तर
- Rust is a reddish-brown coloured hydrated ferric oxide layer deposited on the surface of iron objects that are exposed to moist air.
- Chemical formula of rust is Fe2O3.xH2O.
- Anode region: \[\ce{Fe_{(s)} -> Fe^{2+}_{ (aq)} + 2e^-}\]
- Cathode region: \[\ce{Fe^{2+}_{ (aq)} -> Fe^{3+}_{ (aq)} + e^-}\]
- Metals get attacked by substances around it such as moisture, acids, etc. Metal is said to ‘corrode’ due to this attack and the process is called corrosion.
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संबंधित प्रश्न
Why do we apply paint on iron articles?
Which metals do not corrode easily?
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Explain how painting of an iron gate prevents it from rusting.
Explain why Iron sheets are coated with zinc during galvanization.
Name the metal which is used for galvanising iron.
In one method of rust prevention, the iron is not coated with anything. Which is this method?
The corrosion of iron is called ______.
The corrosion of copper produces a ______ coating of basic copper carbonate on its surface.
Why is an iron grill painted frequently?
Name five methods of preventing rusting of iron.
What are the special properties of stainless steel?
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of ______.
Four metals P, Q, R and S are all obtained by the reduction of their oxides with carbon. Metal P is used to form a thin layer over the sheets of metal S to prevent its corrosion. Metal Q is used for electroplating tiffin boxes made of metal S whereas metal R is used in making car batteries. Metals Q and R form an alloy called solder. What are metals P, Q, R and S? How have you arrived at this conclusion?
Bronze is an alloy of ______.
Name the metal which is a constituent of blood pigment?
Name the metal which is a constituent of plant pigment?
Compare roasting and calcination.
No chemical reaction takes place when granules of a 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.
(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.
(ii) Mention any two types of reactions under which above chemical reaction can be classified.
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.
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
A wooden article should be polished.
Give reason.
Copper and brass utensils should be tinned.
To prevent corrosion of iron and steel _______ method is used.
When one of the metals in an alloy is mercury the alloy is called _______.
Find the correlation:
Bronze : ______ :: Tin : Cu+Zn.
Match the columns.
| Group A | Group B |
| 1) Electroplating | a) Pressure cooker |
| 2) Anodising | b) Silver plated spoons |
| c) Coating of tin on copper | |
| d) Coating of Zinc on iron |
Draw a neat labelled diagram.
Electrolysis
Draw a neat labelled diagram.
Anodizing
What is rust?
Give solutions by giving examples of corrosion?
Identify the correct statement from the following:
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Explain the chemical reactions in rusting of iron.
