-OH group in alcohol is responsible for polarity and solubility.
Explanation
Each alcohol consists of a carbon chain (always nonpolar) and an OH group (polar). For ethanol, for example, the chemical formula looks like this: C2H5OH. So ethanol has a 2 carbon chain and an OH group. As water is polar, it attracts the OH group. The carbon chain, on the other hand, as nonpolar, is repelled. The solubility of alcohols is therefore determined by the stronger of the two forces.
Solubility of alcohol in water
Alcohols are soluble in water. This is due to the hydroxyl group in the alcohol, which is able to form hydrogen bonds with water molecules. Alcohols with a smaller hydrocarbon chain are very soluble. As the length of the hydrocarbon chain increases, the solubility in water decreases. With four carbon in the hydrocarbon chain and higher, the decrease in solubility becomes visible as the mixture forms two immiscible layers of liquid.
