During explosion of gunpowder, which of the following gases are evolved in the proportion of 1:3?

The correct answer is Option 3: Nitrogen : Carbon dioxide.

Gunpowder, or black powder, typically consists of Potassium Nitrate (KNO₃), Sulfur (S), and Charcoal (C). While the exact reaction can vary depending on the ratio of ingredients, a standard balanced chemical equation for the combustion of gunpowder is:

10KNO₃ + 3S + 8C → 2K₂CO₃ + 3K₂SO₄ + 6CO₂ + 5N₂

However, in simplified or specific theoretical models of gunpowder explosion, the reaction is often represented as:

2KNO₃ + S + 3C → K₂S + N₂ + 3CO₂

• In this reaction, one mole of Nitrogen (N₂) is produced for every three moles of Carbon dioxide (CO₂).
• This results in a molar ratio of 1:3 between Nitrogen and Carbon dioxide.

Options 1 and 2 are incorrect because free Oxygen is consumed as an oxidizer rather than evolved as a major product. Option 4 is incorrect as it reverses the required 1:3 proportion.