What is an alcohol?

In chemistry, an alcohol is an organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. The general formula for alcohols homologous series is CnH2n+1OH (when n ≥ 1). In common terms, the word alcohol refers to ethanol, the type of alcohol found in alcoholic beverages. There are three major subsets of alcohols: primary (1°), secondary (2°) and tertiary (3°), based upon the number of carbon atoms the C-OH group's carbon (shown in red) is bonded to.





No. of Carbon atoms (C):
Name of Alcohols (-ol):
Alcohols formula (CnH2n+1OH):

• 1 C atom
  Methanol
  CH3OH

• 2 C atoms
  Ethanol
  C2H5OH

• 3 C atoms
  Propanol
  C3H7OH

• 4 C atoms
  Butanol
  C4H9OH

• 5 C atoms
  Pentanol
  C5H11OH

Alcohols are covalent molecules with physical properties of:

- colourless liquids

- have low boiling points

- soluble in water

As no. of carbon atoms increases, boiling points, melting points and the density of alcohols increase too but their solubility in water decreases.

Uses of ethanol:

i) making alcoholic drinks

ii) industrial solvent

iii) making perfume