Notes On Alcohols And Phenols: Classification And Nomenclature - CBSE Class 12 Chemistry
Alcohols have one or more hydroxyl groups attached to a carbon atom. Phenols have one or more hydroxyl groups attached to a benzene ring. Alcohols and phenols can be classified as primary, secondary or tertiary. Some alcohols can be described as allylic, benzylic or vinylic alcohols. In IUPAC nomenclature, the alcohol name is derived from the alkane name of the longest continuous carbon chain. IUPAC nomenclature of alcohols uses the "-ol" ending. Ex: In IUPAC nomenclature, dihydroxy benzene derivatives are named as diols. Phenol derivatives can be named as substituted phenols, but many have common names. The dihydroxyl benzene derivatives are actually better known by their common names. Ex: Benzene-1,2-diol is known as catechol (or) pyrocatechol. Benzene-1,3-diol is commonly referred to as resorcinol. Hydroquinone (or) just quinol, is the common name of Benzene-1,4-diol.

#### Summary

Alcohols have one or more hydroxyl groups attached to a carbon atom. Phenols have one or more hydroxyl groups attached to a benzene ring. Alcohols and phenols can be classified as primary, secondary or tertiary. Some alcohols can be described as allylic, benzylic or vinylic alcohols. In IUPAC nomenclature, the alcohol name is derived from the alkane name of the longest continuous carbon chain. IUPAC nomenclature of alcohols uses the "-ol" ending. Ex: In IUPAC nomenclature, dihydroxy benzene derivatives are named as diols. Phenol derivatives can be named as substituted phenols, but many have common names. The dihydroxyl benzene derivatives are actually better known by their common names. Ex: Benzene-1,2-diol is known as catechol (or) pyrocatechol. Benzene-1,3-diol is commonly referred to as resorcinol. Hydroquinone (or) just quinol, is the common name of Benzene-1,4-diol.

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