Petrol is probably the best known of all the products from crude oil. Just under 20% of a barrel of crude oil goes to making petrol - the largest proportion for a single product.
Petrol (also called gasoline) is made from the fraction that we call naphtha. Petrol is the product and naphtha is what comes out of the distillation column. It is a mixture of hydrocarbons with between 5 and 10 carbons in their chains
Of all the products, petrol probably has the most branching journey through the refinery. The final blending process takes naphthas and additives that have come from a number of sources.