If a mixture of kerosene and water is left undisturbed for a while, which liquid comes to the bottom and which will be at the top?
Water stays at the bottom and kerosene at the top.
Kerosene and water do not mix. If we add kerosene to the water, you then must expend more energy and effort to separate them before you can use either the water or the kerosene. Kerosene floats on the surface of the water because of kerosene is lower than the water.
It is based on the density of the liquids. The liquid that is lighter (less density) goes over the top of the other liquid having a higher density.
In this case, kerosene has a density of 820 kg/m3 and water has 1000 kg/m3. So, kerosene remains at the top and the water comes down.