Naphtha in a beaker. Naphtha is a product of the refining of crude oil. Crude oil is a mixture of hydrocarbons that is heated to separate it into parts called fractions. The lighter hydrocarbon fractions boil off and leave the heavier fractions behind. Naphtha is collected in the range 60-100 degrees Celsius, and has hydrocarbons with 5-9 carbon atoms. Naphtha is an intermediate product that is processed to produce petrol for use as a fuel in motor vehicles. To compare the colour and viscosity of crude oil and its fractions, see T110/483-491 and T110/492-501.