Question

Give reasons for the following. a. aluminium foils are used to wrap food items. b.immersions rods for heating liquid are made up of metalic substance. c. copper cannot displace zinc from its salt solution. d.sodium and potasium are stored in kerosene.

Answer 1

A. Because it is highly mellable. B. Because metals are good conductors of heat and electricity. C. As copper is less reactive than zinc. D. As they can be react with oxygen if stored in open. A lot of heat is produced in this reaction so they are always stored in kerosene.

Answer 2

Answer:

(a) Aluminium foils are used to wrap food items because aluminium metal is malleable. Therefore, it can be beaten into thin foils.

(b) Metals are good conductors of heat and electricity. Therefore, immersion rods for heating liquids are made of metallic substances.

(c) A metal can displace a less reactive metal from its salt in an aqueous solution. But zinc is more reactive than copper. Therefore, copper cannot displace zinc from its salt solution.

Cu(s)+ ZnSO4 (aq) → No reaction

(d) Sodium and potassium are stored in kerosene because they are highly reactive elements. They can easily catch fire even when in contact with air.