Question

In petroleum wells,the oil is found above water.why?

Answer 1

Oil is non polar and water is polar in nature so they will not mix.

Also density of petroleum is less than water.So as you know,less dense liquid will be on more dense liquid.
The density of petroleum is lesser than water. And petroleum is immiscible with water.

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Tripathy

Answer 2

Oil is less dense than water . The particles in oil are bigger and occupy large space that makes it less denser than water.

And since the water and oil do not mix i.e they are immiscible liquids the oil is found above water.

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