The bulk of a typical gasoline consists of hydrocarbons with between $4$ and $12$ carbon atoms per molecule (commonly referred to as $\text{C4}-\text{C12}$). It is a mixture of paraffins (alkanes), cycloalkanes (naphthenes), and olefins (alkenes), where the usage of the terms paraffin and olefin is particular to the oil industry. The actual ratio depends on:

• The oil refinery that makes the gasoline, as not all refineries have the same set of processing units;
• The crude oil feed used by the refinery;
• The grade of gasoline, in particular, the octane rating.

Below carbon atoms per molecule are mentioned.

(i) Gasoline ${\mathrm{C}}_6-{\mathrm{C}}_{10}$

(ii) Kerosene ${\mathrm{C}}_{10}-{\mathrm{C}}_{13}$

(iii) Gas oil ${\mathrm{C}}_{13}-{\mathrm{C}}_{18}$