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प्रश्न
| 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.
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उत्तर
- In this process, the anode is an aluminium object to be coated, and the electrolyte is diluted sulfuric acid.
- When aluminium oxide is applied to an object made of aluminium, corrosion resistance is increased.
- The technique is known as 'Anodising'.
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संबंधित प्रश्न
What is an alloy?
Give two examples of alloys with their chemical composition.
Write two methods of preventing the rusting of iron.
Two methods by which rusting of iron can be prevented are ______ and ______.
Explain why rusting of iron objects is faster in coastal areas than in deserts.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
What is meant by galvanisation? Why is it done?
Name the metal which is used for galvanising iron.
Fill in the following blank with suitable word:
The process of depositing a thin layer of zinc on iron articles is called .............
Fill in the following blank with suitable word:
The corrosion of copper produces a .............. coating of basic copper carbonate on its surface
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
Name a common metal which is highly resistant to corrosion.
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?
Name the metal which is a constituent of plant pigment?
What is corrosion? What are necessary conditions for corrosion?
State under what conditions corrosion is faster ?
Identify the process shown in the diagram and explain it in short
Answer the following question.
List two properties of alloys.
Give reason.
An iron article should be given a coat of paint
Give reason.
Copper and brass utensils should be tinned.
Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
Write a short note on Alloying.
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?
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
Pressure cooker : Anodizing : : Silver plated spoons : _______
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Find the odd one out and give its explanation.
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 |
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Explain concept with example/explain with the help of a balanced equation.
Corrosion
Give preventive methods by giving examples of corrosion?
What is rust?
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
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.
Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety of structures, from hand-held sculptures to massive pillars and buildings.
The substance not likely to contain CaCO3 is:
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?
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
Explain the chemical reactions in rusting of iron.
