Explosives in civil works — composition of traditional gunpowder The proportions by weight of charcoal, saltpetre (potassium nitrate), and sulphur in black gunpowder are, respectively:

Introduction / Context:
Historic blasting agents such as black powder appear in questions on construction safety and materials. Knowing the typical composition clarifies performance (burning rate, smoke) and the shift to modern explosives in civil engineering.

Given Data / Assumptions:

• Black powder components: saltpetre (oxidizer), charcoal (fuel), sulphur (fuel and sensitizer).
• Proportions are by weight.

Concept / Approach:
The classic black powder formulation uses approximately 75% potassium nitrate, 15% charcoal, and 10% sulphur. The oxidizer portion dominates to rapidly supply oxygen for combustion of the fuels, while sulphur lowers ignition temperature and improves granulation.

Step-by-Step Solution:
Identify role of each component.Recall standard ratio 75:15:10 for KNO3:charcoal:sulphur.Map to the order asked (charcoal, saltpetre, sulphur) → 15, 75, 10.

Verification / Alternative check:
Multiple references report 75/15/10 by weight as the common mix, confirming the selection.

Why Other Options Are Wrong:
Other permutations invert roles, either starving the oxidizer or overwhelming with sulphur, which would not match typical performance.

Common Pitfalls:
Forgetting the requested order and answering in KNO3-first format; always align the sequence with the question.

Final Answer:
15, 75, 10