Question

The incomplete combustion of petrol or diesel leads to the emission of which poisonous gas-

• A. Carbon dioxide
• B. Carbon monoxide
• C. Methane
• D. Ozone

Answer 1

The correct option is B Carbon monoxide

When petrol or diesel goes through the complete combustion then it forms carbon dioxide and water molecules.
$2C_8{H}_{18}+25O_2\to 16C{O}_2+18H_{2}O.$
But when the supply of air/oxygen is poor then incomplete combustion occur. In incomplete combustion water is still produced, but carbon monoxide and un-burnt carbon particles are released instead of carbon dioxide. Carbon monoxide is a poisonous gas which can lead to many diseases.
In general, for incomplete combustion:
Hydrocarbon + oxygen $\to$ carbon monoxide + carbon + water.