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प्रश्न
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
पर्याय
electroplating
anodization
tinning
alloying
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उत्तर
tinning
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Write two methods of preventing the rusting of iron.
What are alloys?
Give reasons:
Platinum, gold and silver are used to make jewellery.
Write a chemical equation to show the process of corrosion of iron.
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 blank with suitable word:
The corrosion of iron is called ................
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
What is corrosion?
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
What are the constituents of stainless steel?
Name a common metal which is highly resistant to corrosion.
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.
A metal X which is resistant to corrosion is produced by the electrolysis of its molten oxide whereas another metal Y which is also resistant to corrosion is produced by the reduction of its oxide with carbon. Metal X can be used in powder form in thermite welding whereas metal Y is used in making cathodes of ordinary dry cells.
(a) Name the metals X and Y.
(b) Which of the two metals is more reactive : X or Y?
(c) Name one ore or metal X. Also write its chemical formula.
(d) Name one ore or metal Y. Also write its chemical formula.
(e) Name one alloy of metal X and one alloy of metal Y.
Bronze is an alloy of ______.
Identify the process shown in the diagram and explain it in short
Write three methods of preventing rusting of iron.
Answer the following question.
List two properties of alloys.
Give reason for the following:
A suspension of rust is basic in nature.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
State whether the statement given below is true or false. If false write the correct statement.
Graphite is a lustrous non-metal which conducts electricity.
_______ forms a green colour in the water.
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.
Coins are made from metals and alloys.
Draw a neat labelled diagram.
Electroplating
What is rust?
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.
What is rust?
Give the equation for the formation of rust.
Copper objects lose their shine and form green coating of ____________.
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?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
In ______ process a layer of molten tin is deposited on metals.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
