(a) State three uses of oxygen, other than artificial respiration. (b) Give tests for oxygen gas.

(a) Uses of oxygen are :

• Spaceships: Liquid oxygen is used for burning fuel in rockets and spaceships as there is no air in the space.
• Cutting and welding: Oxygen and hydrogen are made to bum in a specially designed torch. The oxyhydrogen flame can easily melt metals and used for cutting and welding them.
• Chemical industry: Oxygen is used in large amount for preparing sulphuric acid from sulphur and nitric acid from ammonia.

(b) Tests for oxygen gas are :

• It rekindles glowing wooden splinter.
• If mixed with colorless nitric oxide gas, it forms reddish brown fumes of nitrogen dioxide.
• It dissolves in alkaline pyrogallol solution and turns it brown.