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प्रश्न
Give reasons for the following.
- Aluminum foils are used to wrap food items.
- Immersion rods for heating liquids are made up of metallic substances.
- Sodium and potassium are stored in kerosene.
- Mercury is used in thermometers.
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उत्तर
- Aluminium is malleable, soft and does not react with food items, so it is used to wrap food items.
- Metals are good conductor of heat and electricity, so immersion rods are made up of metallic substances.
- Sodium and potassium are very reactive, they react with air and water, so they are stored in kerosene.
- Mercury is used in thermometers and barometers because of its high density and uniform expansion at different temperature.
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संबंधित प्रश्न
A metal with melting point less than 50°C is
Write ‘True’ or ‘False’ in front of following statement.
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Take an element from an alkali metal and one from an alkaline earth metal and write an equation for their action with:
Water.
With reference to the following metals state their use in daily life metal:
copper
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Aakash noticed that the metal latch on gate was difficult to open during hot sunny days. However, it was not difficult to open the same latch at night. Aakash observed that the latch and the gate are exposed to the sun during day time.
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- Briefly state how you would test the hypothesis.
The ability of metals to be drawn into thin wire is known as
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| i. | Softest metal | a. | Copper |
| ii. | Hardest metal | b. | Sodium |
| iii. | Hardest non–metal | c. | Osmium |
| iv. | Ductility | d. | Diamond |
Which metal has the highest ductility?
Which metals are not solid at room temperature?
