CBSE Class 10 Science 2017 · Paper 31/2/2 · Question 6

Products of combustion: carbon dioxide (${\text{CO}}_2$), water vapour, sulphur dioxide (${\text{SO}}_2$) and oxides of nitrogen; when the supply of air is insufficient, carbon monoxide ($\text{CO}$) and unburnt carbon particles (soot) as well. Harmful effects: carbon dioxide is a greenhouse gas, so more of it in the air causes global warming; sulphur dioxide and oxides of nitrogen dissolve in rain water to form acids and cause acid rain, which damages soil, water bodies, plants and buildings, and they are poisonous at high concentrations; carbon monoxide is a poisonous gas; soot pollutes the air as smoke and haze and causes breathing problems.