Alcohols, Carboxylic Acids and Esters

carbon-based molecules that contain the functional group -OH.

Methanol,ethanol and propanol are the first three memebers of the homologous series of alcohols.

Alcohols:

• dissolve in water to form neutral solutions
• react with sodium to produce hydrogen
• burn in air
• are used as fuels and solvents

Alcoholic drinks contain ethanol. Ethanol can be oxidised to ethanoic acid either by chemical oxidising agents or by microbial action.

Ethanoic acid is the main acd in vinegar.

Carboxylic acids are carbon- based molecules that contain the functional group -COOH.

They..

• dissolve in water to form acidic solutions
• react with carbonates (sodium carbonate) to produce carbon dioxide
• react with alcohols (in the presence of an acid catalyst) to form esters.

CARBOXYLIC ACIDS DON'T IONISE FULLY IN WATER, SO THEY ARE CALLED WEAK ACIDS.

AQUEOUS SOLUTIONS OF WEAK ACIDS HAVE A HIGHER PH THAN AQEOUS SOLUTIONS OF STRONG ACIDS WITH THE SAME CONCENTRATION.

Alcohols and carboxylic acids react together to form esters. When ethanol and ethanoic acid react together the ester formed is ethyl ethanoate.

Esters contain the functional group -COO

Esters are volatile compounds (meaning they have a low boiling point)

The have distinctive smells, so are used in perfumes and as flavourings in food.