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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
Give two examples of alloys with their chemical composition.
Write two methods of preventing the rusting of iron.
Why do we apply paint on iron articles?
Explain the terms Corrosion
What is anodising? Give its applications.
Explain why, iron sheets are coated with zinc.
State two conditions for the rusting of iron.
Fill in the following blank with suitable word:
The process of depositing a thin layer of zinc on iron articles is called .............
Fill in the following blanks with suitable words:
Tiffin boxes are electroplated with .............. but car bumpers are electroplated with ............... to protect them from rusting.
Fill in the following blank with suitable word:
The corrosion of copper produces a .............. coating of basic copper carbonate on its surface
Why is an iron grill painted frequently?
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:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate
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.
Name the metal which is a constituent of blood pigment?
Identify the process shown in the diagram and explain it in short
Answer the following question.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.
Find the odd man out:
What is ‘rusting’?
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.
Find the odd one out and give its explanation.
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
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.
Give preventive methods by giving examples of corrosion?
What is rust?
Give the equation for the formation of rust.
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Amalgam is an alloy of ____________.
Galvanisation is a process used to prevent the rusting of which of the following?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Explain the chemical reactions in rusting of iron.
In ______ process a layer of molten tin is deposited on metals.
