Q6. Give reasons for the following.
(a) Aluminum foils are used to wrap food items.
Answer – Because it does not react with food items. It is soft. It is malleable and easily beaten in sheets to make its foil for wrapping food items etc.
(b) Immersion rods for heating liquids are made up of metallic substances.
Answer – Because metal is a good conductor of heat and electricity. When the electric current passed through the metallic rod, it gets hot very soon and warms the water.
(c) Copper cannot displace zinc from its salt solution.
Answer – Zinc is more reactive than copper. So, copper can’t displace it.
Cu + ZnSO4 ——-> No reaction.
(d) Sodium and potassium are stored in kerosene.
Answer – Sodium and potassium are stored in Kerosene. Because sodium and potassium are so highly reactive. They can easily catch fire even when in contact with air.