Hydroxy Compounds

A hydroxy or hydroxyl group is a functional group composed of one oxygen atom covalently bonded to one hydrogen atom and having the chemical formula OH. Compounds such as alcohols, phenols, and carboxylic acids contain these groups.

Course Contents

  • Alcohols (exemplified by ethanol)
  • (i) formation of halogenoalkanes
  • (ii) reaction with sodium; oxidation; dehydration
  • (iii) the tri-iodomethane test
  • Phenol
  • (i) its acidity; reaction with bases and sodium
  • (ii) nitration of, and bromination of, the aromatic ring

Learning Outcomes

Candidates should be able to:

  • (a) recall the chemistry of alcohols, exemplified by ethanol:
  • (i) combustion
  • (ii) nucleophilic substitution to give halogenoalkanes
  • (iii) reaction with sodium
  • (iv) oxidation to carbonyl compounds and carboxylic acids
  • (v) dehydration to alkenes
  • (b) suggest characteristic distinguishing reactions for the different classes of alcohols (primary, secondary and tertiary alcohols), e.g. mild oxidation
  • (c) deduce the presence of a CH3CH(OH)– group in an alcohol from its reaction with alkaline aqueous iodine to form tri-iodomethane
  • (d) recall the chemistry of phenol, as exemplified by the following reactions:
  • (i) with bases
  • (ii) with sodium
  • (iii) nitration of, and bromination of, the benzene ring
  • (e) explain the relative acidities of water, phenol and ethanol in aqueous medium (interpret as BrønstedLowry acids)