Physical Properties

1. Solubility: The lower fatty acids like acetic and butyric acids are soluble in water. Higher fatty acids from caproic acid onwards are insoluble in water.
2. Melting point: Fatty acids differ in their melting points; generally, the melting point is lowered if
   1. fatty acids are unsaturated and
   2. fatty acids have shorter chain lengths.
3. Spreading: The phenomenon of spreading is the property of the fatty acids contained in the fat and refers to the formation of a thin and uniform layer of fat or oil when placed over the surface of water.