Chemical Properties of Acids

The chemical properties of acids are determined
largely by the carboxyl group. All form metallic salts that have a wide range of
commercial use. In addition, the unsaturated acids have chemical properties characterized
by the double bond, as described under unsaturated hydrocarbons in Sec.
5.2. The unsaturated acids may be reduced with hydrogen to give corresponding
saturated acids.
Organic acids serve as food for many microorganisms and are oxidized to carbon
dioxide and water. Ease and rate of oxidation are believed to be enhanced by the
presence of unsaturated linkages. The rate of biological attack on high-molecularweight
fatty acids is often limited by their solubility in water. This is a particular
problem in sludge digesters where fatty materials tend to float and segregate themselves
in a scum layer.