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प्रश्न
Gold and silver are used to make jewellery. Give reason
उत्तर
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संबंधित प्रश्न
Give reasons for the following.
Aluminium foils are used to wrap food items.
Name two metals which are used for making electric wires.
Name the non-metal which is used to make electrodes of dry cells.
Metals are said to be shiny. Why do metals generally appear to be dull? How can their brightness be restored?
Name a non-metal which conducts electricity.
Write ‘true’ or ‘false’ for the following statement
Sodium can be cut with a knife.
State any five physical properties of a metal.
Physical properties of a metal :
Name one metal which is a liquid at room temperature
Name:
Two metals which are liquid at room temperature
Explain the term Minerals.
In which of the following industries, microbial enzymes are not used?
a) Glass industry.
b) Cheese industry
c) Tanning industry.
d) Paper industry.
Write scientific reason.
Sodium metal is kept in kerosene.
Which metal occurs as an oxide also gives the name of their respective ore.
Explain the following:
Metals like calcium and magnesium are never found in their free state in nature.
Give reason for the following:
Metals form cations while non-metals form anions.
The sound of one metal colliding with another makes a noise, this property is called as _______.
Diamond is a hard substance.
Which of the following non-metals is a liquid?
Match the following:
| 1. | Non-metals | a. | Silicon |
| 2. | Metals | b. | fire extinguisher |
| 3. | Metalloids | c. | dull and soft |
| 4. | Oxygen | d. | hard and shiny |
| 5. | Water | e. | supports fire |
Paheli bought a statue made up of copper. To her surprise, it acquired a dull green coating after a couple of months. Explain the reason.
