note preview  Acids, Bases and Salts  Synopsis Substances are classified into acids, bases and salts depending on their chemical behavior and properties. Acids are of sour taste and turn blue litmus to red. Bases are soapy to touch and turn red litmus to blue. According to Lewis, electron pair acceptor is an acid and electron pair donor is a base. The strength of acid or base depends on the concentration of H3O H3O + ions are fewer then it is a weak acid. A scale for measuring hydrogen ion concentration in a s