Definition and Uses :
It acts as a weak organic acid. Carboxylic acids donate hydrogen ions if a base is available to accept them. In this way, they react with both organic (e.g., amines) and inorganic bases. Their reactions with bases, called "neutralizations," are accompanied by significant amounts of heat. Neutralization between an acid and a base forms water plus a salt.
Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are poorly soluble in water. Soluble carboxylic acids dissociate from some water to yield hydrogen ions. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve because neutralization forms a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt.
Carboxylic acids, like other acids, react with cyanide salts to form gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with cyanide solutions to release gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are produced by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrites, and sulfides.