Physical properties of alcohols and phenols

Alcohols and phenols consist of two parts, an alkyl/aryl group and a hydroxyl group. The properties of alcohols and phenols are due to the OH group.The alkyl and aryl groups modify these properties.
The boiling points of alcohols and phenols increase with increase in the number of carbon atoms. This is due to increase in van der Waals forces. In alcohols, the boiling points decrease with increase in branching. The reason is that when branching increases, vander Waals forces decreases due to decrease in surface area.
The –OH group in alcohols and phenols contain a hydrogen bonded to an electronegative oxygen atom. Therefore, it is capable of forming hydrogen bond.
Alcohols and phenols have higher boiling points than the corresponding other classes of compounds namely hydrocarbons, ether and halo alkanes/haloarenes of comparable molecular masses due to the presence of intermolecular hydrogen bonding in them.
The solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules. The solubility decreases with increase in size of the hydrophobic group (R).

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