Question

if densities of water and honey are different why do they mix whereas oil and water does not mix

Answer 1

Oil molecules are non-polar – they have no charge. Because of this, oil molecules are more attracted to each other than to water molecules, and water molecules are more attracted to each other than to oil molecules. Oil and water can be forced to mix together by adding an emulsifier.

Answer 2

In solubility theory, like attracts like. It means polar molecules are attracted by polar molecules and non-polar molecules are attracted by non-polar molecules. Water and honey are polar molecules and oil is non-polar. As honey is denser than the water, it will sink. While it is moving through the water, it will begin to dissolve. Depending on the water content in the honey and the relative proportions of the constituent sugars, the honey will dissolve about as fast as sugar. However, oil molecules are hydrophobic (water fearing) and does not attracted to water molecules and remain as such and do not mix.