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प्रश्न
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
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उत्तर
Because silver amalgam melts at low temperatures and may easily fill cavities, it is used to fill cavities.
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संबंधित प्रश्न
Write two methods of preventing the rusting of iron.
Why do we apply paint on iron articles?
Explain the term corrosion.
Give reasons:
Platinum, gold and silver are used to make jewellery.
Two methods by which rusting of iron can be prevented are ______ and ______.
The chemical reaction involved in the corrosion of iron metal is that of ______.
In one method of rust prevention, the iron is not coated with anything. Which is this method?
Why is an iron grill painted frequently?
Name any two metals which do not corrode easily.
Name five methods of preventing rusting of iron.
What are the constituents of stainless steel?
What are the special properties of stainless steel?
Name an alloy of copper. State its chemical composition and any one use.
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
Bronze is an alloy of ______.
Explain how the activity series accounts for each of the following:
tendency to corrosion
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.
What is done to prevent corrosion of metals?
Choose the correct alternative and rewrite the following:
Iron is _____________________.
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
Copper and brass utensils should be tinned.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
_______ is an alloy made from iron, carbon and chromium.
Corrosion of silver causes a black layer of _______.
When one of the metals in an alloy is mercury the alloy is called _______.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Find the odd one out and give its explanation.
Draw a neat labelled diagram.
Anodizing
What is rust?
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
Give preventive methods by giving examples of corrosion?
What is rust?
State two conditions necessary for rusting of iron.
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.
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
