question_answer 6)

Give reasons for the following. (a) Aluminium foils are used to wrap food items. (b) Immersion rods for heating liquids are made up of metallic substances. (c) Copper cannot displace zinc from its salt solution. (d) Sodium and potassium are stored in kerosene.  

Answer:

(a) Aluminium is metal (i.e., malleable) soft and does not react with food materials.Therefore aluminium foils are used to wrap food items. (b) Metals are good conductor of heat and electricity. So immersion rods are made of metallic substance.   (c) Copper is less reactive than zinc. Therefore copper cannot displace zinc from its salt solution.                                                                             (d) Sodium and potassium react most vigorously with the oxygen in air to form their oxides. Therefore sodium and potassium are stored in kerosene.