Benzene is insoluble in water according to the reasons mentioned below:
Benzene is a symmetrical compound and thus it has zero dipole moment and is non-polar, while water is a polar compound possessing dipole moment, therefore, due to variable polarity, benzene and water cannot mix.
Both the carbon and hydrogen in benzene are equidistant and hence the net charge is balanced. Because of the ring structure, the net dipole moment is zero, therefore, mixing the charged liquid and uncharged liquid is not possible which results in a failure.