Question

Gun powder catches fire even in the absence of air.

• A. The gun powder is itself combustible.
• B. The gun powder require oxygen for burning.
• C. The gun powder itself contain oxygen for burning.
• D. All of the above.

Answer 1

The correct option is A The gun powder is itself combustible.

Gun powder does not need air to combust as its ingredients itself react to produce heat and flame. The constituents of gun powder are saltpetre(potassium nitrate) 75%, charcoal 15% and sulphur 10%. Potassium nitrate reacts with charcoal and sulphur to produce potassium sulphide, $C{O}_2$ gas and $N_2$ gas along with heat. Potassium nitrate contains plenty of oxygen to ensure good combustion. Nitrogen and carbon dioxide gas at normal temperature and pressure, occupy 280 times the volume of original powder leading to an explosion.