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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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