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प्रश्न
Write scientific reason.
Coins are made from metals and alloys.
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उत्तर
- Coins are made from metals and alloys because metals and their alloys possess the property of malleability. So, they can be hammered into flat shape without breaking.
- Metals and alloys used for making coins should be corrosion resistance and bright in colour. They should also be hard and wear resistance.
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संबंधित प्रश्न
Which metals do not corrode easily?
Explain how painting of an iron gate prevents it from rusting.
Name the metal which is used for galvanising iron.
The process of depositing a thin layer of zinc on iron articles is called ______.
______ and ______ are necessary for the rusting of iron.
Name any two metals which do not corrode easily.
With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.
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 special properties of stainless steel?
Name an alloy of copper. State its chemical composition and any one use.
A common metal which is highly resistant to corrosion is ______.
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 ______.
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Mention two uses of the following metals and non-metals
Iron
Name the metal which is a constituent of blood pigment?
Explain how the activity series accounts for each of the following:
tendency to corrosion
State under what conditions corrosion is faster ?
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.
Observe the following picture a write down the chemical reaction with the explanation.
Identify the process shown in the diagram and explain it in short
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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.
Pressure cooker : Anodizing : : Silver plated spoons : _______
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
Draw a neat labelled diagram.
Anodizing
Complete flow chart given below.
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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?
Give the equation for the formation of rust.
State two conditions necessary for rusting of iron.
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Gold plated ornaments is the example of ______.
