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प्रश्न
Write three methods of preventing rusting of iron.
उत्तर
Three methods of preventing rusting of iron:
A. Galvanizing: It is a process of giving a thin coating of zinc on iron or steel to protect them from corrosion, E.g. shiny iron nails. pins etc.
B. Rusting of iron can be prevented by coating it with paint, oil, grease or varnish.
C. Tinning: In this process thin layer of tin is coated over iron objects.
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संबंधित प्रश्न
Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
D. Bessemerisation
Explain why, iron sheets are coated with zinc.
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
What is the corrosion of iron known as?
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
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?
Choose the correct alternative and rewrite the following:
Iron is _____________________.
Give a reason why rust turns moist red litmus blue.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
To prevent corrosion of iron and steel _______ method is used.
Stainless steel is an alloy of _______.
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.
Anodizing
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
Observe the following figure and write the answer of the question.
- Which process is shown in the figure?
- Explain the chemical reaction shown in the figure.
- Write the reactions on anode and cathode.
The process of coating the surface of the metal with a thin layer of zinc is called ______
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:
Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
| 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.
