Reactions
Bases
Like all acids, carboxylic acids react with bases and metals as an acid/base reaction. The reaction with Sodium carbonate can be used to distinguish between carboxylic acids and alcohols.
Decarboxylation
This is a reaction which can be used to reduce the carbon chain by 1 by fusing the carboxylic acid with sodium hydroxide. The functional group will be lost.
Halogenation
Carboxylic acids, just like alcohols react with PCl5 in order to substitute the OH group with a Cl. This would prepare the reactive acid chloride that can be used in synthesis.
Esterification
From Halogenoalkanes
From Alcohols
This is the household reaction for the production of an ester, although it must be noted that it is not the most efficient, especially considering that the equation is in equilibrium.
The sulfuric acid would act both as a catalyst and as a dehydrating agent.