Hint: Here we will proceed by defining the term alkyl halides and then we will be discussing how alkyl halides are polar by their attraction force and immiscible (not forming a homogeneous mixture when formed) with water.
Complete answer: Alkyl Halides: Alkyl halides (also known as haloalkanes) are compounds in which one or more hydrogen atoms in an alkane have been replaced by halogen atoms (fluorine, chlorine, bromine or iodine). Energy is required to overcome the attractions between the haloalkene molecules and to break the hydrogen bonds between water molecules. The energy released during the formation of new attractive force between the haloalkene and the water molecule is very less as the attraction between the haloalkene and the water molecule is not as strong as the original hydrogen bonds in water. All the halogen derivatives of hydrocarbons are polar in nature but they are insoluble in water, because they are unable to form hydrogen bonds already present in water. Haloalkanes are not very soluble in water because they cannot form hydrogen bonds, and the energy required to break hydrogen bonds in water etc is higher than the energy released when new bonds between the haloalkane and water are formed. Alkyl halides are polar in nature due to electronegativity differences between carbon and halogen atoms. Halogens are more electronegative than carbon, due to which bonded electrons get shifted towards the halogen atom making the bond polar.
Thus, alkyl halides though polar are immiscible with water.
Note: Polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms.