Explosives – composition of traditional gunpowder Classic gunpowder (black powder) is a mechanical mixture of charcoal, sulfur, and which oxidizing salt?

Introduction / Context:
Gunpowder (black powder) is one of the earliest propellants/explosives. Knowing its composition is basic knowledge in chemical technology and safety. It illustrates the combination of fuel, sulfur sensitizer, and oxidizer in a granular mixture.

Given Data / Assumptions:

• Fuel component: charcoal (carbon).
• Sensitizer/combustion modifier: sulfur.
• Oxidizer must supply oxygen rapidly upon ignition.

Concept / Approach:
The oxidizing component of black powder is potassium nitrate, historically called saltpetre (or salt petre). Upon ignition, KNO3 decomposes to provide oxygen, enabling rapid combustion of carbon and sulfur. The other listed substances are different high-energy materials or fuels not used in classical black powder formulation.

Step-by-Step Solution:

Verification / Alternative check:
Standard references cite typical weight ratios (e.g., 75% KNO3, 15% charcoal, 10% sulfur) for black powder, confirming the oxidizer identity.

Why Other Options Are Wrong:

• Glycerene / nitroglycerene / dynamite: Unrelated to black powder; nitroglycerin and dynamite are separate, later high explosives.

Common Pitfalls:
Mixing up black powder with smokeless powders (nitrocellulose-based) or high explosives; compositions and behaviors are very different.

Final Answer:
salt petre