Hydrocarbons: explain question

Alkanes are generally unreactive towards polar reagents such as concentrated sulfuric acid and aqueous potassium manganate(VII), yet they react readily with chlorine in the presence of ultraviolet light. When alkanes are used as fuels in an internal combustion engine, carbon monoxide, oxides of nitrogen and unburnt hydrocarbons are produced.

Explain the unreactivity of alkanes towards polar reagents, and explain how carbon monoxide, oxides of nitrogen and unburnt hydrocarbons are formed and how they are removed from the exhaust gases.