Question

When combustion of coal takes place in insufficient air (oxygen) which gas is formed . Instead of carbon dioxide

• A. Sulphur dioxide
• B. Nitrous oxide
• C. Carbon monoxide
• D. Nitrogen peroxide

Answer 1

Answer: (C)

Fuels burn when they react with oxygen in the air. If there is plenty of air, complete combustion happens. Coal is mostly carbon. During complete combustion, carbon is oxidized to carbon dioxide:
carbon + oxygen -- carbon dioxide
If there is insufficient air for complete combustion, incomplete combustion (also called partial combustion) happens. Hydrogen is still oxidized to water, but carbon monoxide forms instead of carbon dioxide.

So, the correct answer is 'Carbon monoxide'.