Question

Composition of gunpowder is:
(A) $\text{S}\,\text{+ }\,\text{charcoal + KN}{{\text{O}}_{3}}$
(B) $\text{S}\,\text{+ }\,\text{coke + KN}{{\text{O}}_{3}}$
(C) $\text{S}\,\text{+ coal + KN}{{\text{O}}_{3}}$
(D) all of the above

Answer 1

Hint: Gun powder is a smokeless powder which is a chemical explosive. This is also known as black power. This powder is mainly used in guns, blasting agents and fireworks.
Saltpetre decomposes in high temperatures.

Complete Solution :
Gun powder is a mixture of $\text{S}\,\text{+ }\,\text{charcoal + KN}{{\text{O}}_{3}}$.
Chemical equation of combustion of gunpowder is represented below-
$\text{2KN}{{\text{O}}_{\text{3}}}\,\text{+}\,\,\text{S}\,\text{+}\,\,\text{3C}\,\,\to \,\,{{\text{K}}_{\text{2}}}\text{S}\,\,\text{+}\,\,{{\text{N}}_{\text{2}}}\text{+}\,\,\text{3C}{{\text{O}}_{\text{2}}}$
The standard composition of gunpowder contains 75 % potassium nitrate which is also known as saltpeter, 15% charcoal and 10% sulphur.
- Firstly gunpowder was known as a black powder which combustion occurs rapidly in the presence of air and left residue in the form of shoot. Different combinations of gunpowder give different effects. In this mixture of gunpowder sulphur and charcoal acts as a fuel while potassium nitrate acts as an oxidizer by acting as a source of oxygen.
So, the correct answer is “Option A”.

Additional information –
- Gunpowder was first discovered in china. Combustion of gunpowder is a multi-step reaction so the by-products of this reaction cannot be easily determined.
- Charcoal is the source of carbon and nitrate especially potassium nitrate acts as a source of oxygen by decomposing in high temperature.

Note: For the combustion of gunpowder there is no need of external air supply. Combustion of gunpowder is an exothermic process. Burning spark of fireworks is due to the burning of charcoal present in the gunpowder.