Alcohols (Cambridge (CIE) IGCSE Co-ordinated Sciences (Double Award)): Revision Note

Alcohols

• All alcohols contain the hydroxyl (-OH) functional group which is the part of alcohol molecules that is responsible for their characteristic reactions

• Alcohols are a homologous series of compounds that have the general formula C_nH_2n+1OH

• They differ by one -CH₂ in the molecular formulae from one member to the next

Table showing the first three alcohols

Name	Formula	Displayed formula
Methanol	CH3OH
Ethanol	C2H5OH
Propanol	C3H7OH

Uses and reactions of alcohol

• Ethanol (C₂H₅OH) is one of the most important alcohols

  • Ethanol can also be represented by its structural formula CH₃CH₂OH

• It is the type of alcohol found in alcoholic drinks such as wine and beer

• It is also used as fuel for cars and as a solvent

• Ethanol will undergo complete combustion and burn in excess oxygen to produce carbon dioxide and water 

C₂H₅OH (l) + 3O₂ (g) → 2CO₂ (g) + 3H₂0 (l)

Alcohol is used to make drinks, as a fuel and in solvents

Photo by NHS Better Health