- like hydrocarbons - alcohols also undergo combustion.
Combustion
Complete combustion of alcohol produces carbon dioxide and water.\
Ethanol burns very easily with a pale yellow flame to form carbon dioxide and water vapour.
- exothermic reaction - produces lot of heat (that is why it is considered an alternate fuel) Ethanol can also undergo incomplete combustion if there is limited volume of oxygen.
Example
methanol burns in oxygen as follows: methanol + oxygen → carbon dioxide + water
Oxidation
- Most alcohols undergo oxidation → when heated with oxidising agent → such as acidified potassium manganate(VII)
- for alcohols with hydroxyl () group bonded to the terminal carbon atom → carboxylic acid will be obtained upon oxidation
Acidified potassium manganate(VII) changes colour from purple to colourless
Example
Example
breathalysers → test amt of alcohol consumed by drivers
- ethanol in persons breath undergoes oxidation in the breathalyser.
- coupled with other reactions → electric current is produced.
- this current indicates level of alcohol present in persons blood
ii) if an alcoholic drink such as wine or beer is left exposed to the air, it will turn sour after a few days.
- caused by action of bacteria from the air
- bacteria oxidises ethanol into ethanoic acid.
Esterification
Alcohols react with carboxylic acids to form organic compounds called esters.