Question

Why can't the crude oil extracted from the earth's crust be used as petrol?

Answer 1

Oil comes out of the ground with a wide variety of characteristics. Some 'crude oil' is almost gasoline quality and some is like tar and the rest is everywhere in between. Most crude will have impurities in it that have to be removed for the fuel or lubricant to be useful. Thus, crude oil has to be refined, cleaned up and separated, to make the fuel, lubricants, tar, asphalt and other products that we use.