Which crude oil fraction is known to be most viscous?

Bitumen is the most viscous crude oil fraction. Its high viscosity is due to its complex mixture of large hydrocarbon molecules that have a high molecular weight. This results in a thick, tar-like consistency, making it suitable for use in road construction and roofing applications.

In contrast, gasoline, kerosene, and diesel are fractions that have lower viscosities, as they consist of smaller hydrocarbon molecules that flow more easily. Gasoline, for example, is a highly volatile fuel with a low viscosity, making it easy to ignite and vaporize. Kerosene, while more viscous than gasoline, is still significantly less viscous than bitumen. Diesel is heavier and more viscous than gasoline and kerosene, but it does not compare to the thickness of bitumen. Understanding the properties of these fractions is essential for their application in various industries, as viscosity directly affects how fluids behave under different conditions.