Question

Give reasons
a) Platinum,gold and silver are used to make jewellery
b) Sodium, Potassium and lithium are stored under oil
c) Aluminum is highly reactive metal yet it is used to make utensils for cooking
d) Carbonate and sulphide ores are usually converted into oxides during the process of extracton

Answer 1

(a) Platinum, gold and silver are used to make jewellery because these are low reactive metals so rarely corrosion occur (In silver) and hence do not lost their shine and lustre.

b.Sodium, potassium, and lithium are stored under oil because metals like sodium and potassium react so, vigorously that they catch fire if kept in the open. Hence, to protect them they are kept immersed in kerosene oil

c.This is because aluminium reacts with oxygen present in air to form a thin layer of aluminium oxide. This oxide layer is very stable and prevents further reaction of aluminium with oxygen. Also, it is light in weight and a good conductor of heat. Hence, it is used to make cooking utensils.

d. Carbonate and sulphide ores are usually converted into oxides during the process of extraction. ... Answer: Obtaining a metal from its oxide is much easier than doing that from a metal sulphide or carbonate. Due to this; metal sulphides and carbonates are first converted to metal oxides during metallurgy.

Answer 2

Answer:

(a) Platinum, gold, and silver are used to make jewellery because they are very

(a) Platinum, gold, and silver are used to make jewellery because they are very lustrous. Also, they are very less reactive and do not corrode easily.

(b) Sodium, potassium, and lithium are very reactive metals and react very vigorously with air as well as water. Therefore, they are kept immersed in kerosene oil in order to prevent their contact with air and moisture.

(c) Though aluminium is a highly reactive metal, it is resistant to corrosion. This is because aluminium reacts with oxygen present in air to form a thin layer of aluminium oxide. This oxide layer is very stable and prevents further reaction of aluminium with oxygen. Also, it is light in weight and a good conductor of heat. Hence, it is used to make cooking utensils.

(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction because metals can be easily extracted from their oxides rather than from their carbonates and sulphides.