Properties of phenol

Phenol is also called carbolic acid. It exhibits several distinctive physical and chemical properties:

State and Smell of Phenol

• Phenol is a colourless-to-white solid when pure, but the commercial product is a liquid with a distinct, sickeningly sweet, and tarry odor.

Solubility

• Phenol is moderately soluble in water, with about 8 g of phenol dissolving in 100 g of water. An increase in the size of the aryl group decreases its solubility.

Boiling Point

• Phenol has a higher boiling point than other hydrocarbons, increasing with more carbon atoms. Boiling Point of Phenol is 181.7℃

Molecular Mass

• The molecular mass of phenol is 94.11 g/mol

Melting Point

• The melting point of phenol is approximately 40.5°C to 41°C (104.9 °F)

Density

• The density of phenol is about 1.07 g/cm³ or 9.9lb/gal

Chemical Properties of Phenol

• Phenols are more acidic than aliphatic alcohols and water, but not as acidic as carboxylic acids.
• They react with active metals such as sodium and potassium to form the corresponding phenoxide, which indicate their acidic nature.
• Phenols exhibit chirality within their molecules due to the absence of planar and axial symmetry in the phenol molecule.

Acidity of Phenol

Phenol is more acidic than aliphatic alcohols due to the resonance stabilization of the phenolate anion. The sp² hybridized carbon atom of the benzene ring attached directly to the hydroxyl group acts as an electron sink, leading to the delocalization of the negative charge on the oxygen atom and an increase in the polarity of the O-H bond.

It allows Phenol to lose a hydrogen ion and form a phenoxide ion, making it a weak acid with a pH of around 6.6. The enhanced acidity of Phenol is attributed to the resonance stabilization of the phenolate anion, which is not present in the conjugate bases of simple alcohols.

Tautomerism of Phenol

Phenol can exist in two tautomeric forms, keto and enol. In the keto form, the oxygen of the hydroxyl group is double-bonded to the carbon of the aromatic ring, while in the enol form, the hydroxyl group is double-bonded to the adjacent carbon of the ring, forming a double bond between the carbon and the oxygen.

The enol form is less stable than the keto form due to the unfavourable charge separation between the oxygen and the carbon atoms. However, resonance, hydrogen bonding, or aromaticity can stabilize the enol form.

Phenol is an aromatic organic compound. Its molecular formula is C₆H₆O. Phenol is characterized by a hydroxyl group attached to a carbon atom that is part of an aromatic ring. It is also known as carbolic acid and consists of hydroxyl and phenyl groups attached to each other. In this article, we look into what phenol is, its structure, its classification, general properties, preparation and reactions, etc.