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प्रश्न
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 |
उत्तर
| Group A | Group B |
| 1) Electroplating | b) Silver plated spoons |
| 2) Anodising | a) Pressure cooker |
APPEARS IN
संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Explain the terms Corrosion
Answer the following question.
What are alloys?
Which of the following methods is suitable for preventing an iron frying pan from rusting?
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
What is anodising? Give its applications.
What type of chemical reaction is involved in the corrosion of iron?
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
Explain why, iron sheets are coated with zinc.
What is the corrosion of iron known as?
What is meant by 'rusting of iron'? With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.
Name five methods of preventing rusting of iron.
What are the special properties of stainless steel?
Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
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?
Observe the following picture a write down the chemical reaction with the explanation.
What is done to prevent corrosion of metals?
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Write three methods of preventing rusting of iron.
Give reason.
An iron article should be given a coat of paint
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.
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?
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Write scientific reason.
Coins are made from metals and alloys.
Draw a neat labelled diagram.
Electroplating
Observe the following diagram and give answers.
- Name this method of prevention of corrosion.
- For prevention of which metal this method is used?
- What is used as anode in this method?
The process of coating the surface of the metal with a thin layer of zinc is called ______
State two conditions necessary for rusting of iron.
The diagram shows the reaction between metal and dil. acid.
What is the reason for different behaviour of Mg in test tube B?
Identify the correct statement from the following:
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?
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from the sun.
- make it look beautiful.
- make it dust-free.
Which of the above statement(s) is/are correct?
Galvanisation is a process used to prevent the rusting of which the following?
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
In ______ process a layer of molten tin is deposited on metals.
