Question

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 1

(a)
Aluminium foils are used to wrap food items because:​

• Aluminium is malleable and can be drawn into thin sheets​
• It also does not react with the food so results in no change in the taste.​

Hence, aluminium foils are used to wrap food items.​

(b)

Immersion rods for heating liquids are made up of metallic substances because,​

• As metals are good conductors of heat and electricity, they are used for making immersion rods.​

• Malleability and ductility are other desired properties, which are useful for making immersion rods in the desired shape​

(c)

Copper cannot displace zinc from its salt solution because,​

• Copper is less reactive as compared to zinc. ​

• Thus, copper cannot displace zinc from zinc sulphate solution. ​

(d)

Sodium and potassium are stored in kerosene because,​

• Sodium and potassium are very reactive.​

• Sodium and potassium when exposed to air tend to catch fire and they also vigorously react with water and oxygen.​

• Therefore, sodium and potassium are stored in kerosene.​