Arsphenamine is also known as salvarsan. It is a synthetic organic arsenic compound that was previously used for treating syphilis. Arsphenamine possess $-$ As $=$ As $-$ linkage. Azo dyes are used to promote epithelial growth in the treatment of ulcers, burns, and other wounds. Many azodyes have anticoagulation action. Azo dyes possess $-\mathrm{N}=\mathrm{N}-$ linkage like arsphenamine which possess $-\mathrm{As}=\mathrm{As}-$ linkage.

Tranquilizers are essential components of sleeping pills. It is the class of chemical compounds used for the treatment of stress and mild or even severe mental diseases. These relieve anxiety stress, irritability or excitement by inducing a sense of well beings.

Aspirin is 2 - acetoxybenzoic acid. It is very effective in reducing or abolishing pain without causing impairment of consciousness, mental confusion, incordination or paralysis or some other disturbance or disorder of the nervous system. It reduces fever (antipyretics) and prevents platelet coagulation.

Due to, it has anti blood clotting action and, therefore, it is widely used to prevent heart attack.

Histamine is a chemical substance that stimulates the secretion of pepsin and hydrochloric acid in stomach. Antacids are designed to prevent the interaction of histamine with the receptors present in the stomach wall. As a result, less HCl is released in stomach.

Histamine contracts the smooth muscles in the bronchi and gut and relaxes other muscles in walls of fine blood vessels. As a result, histamine causes allergy. Antihistamines interfere with the natural action of histamine by competing with histamine for binding sites of receptor where histamine exerts its effect.

Since, antiallergic and antacids drugs work on different receptors, therefore, antihistamines remove allergy while antacids remove acidity.

Chemical substances which concentrates at the surface of the solution or interfaces, from surface films, reduces surface tension of the solution and help in removing dirt and dust by emulsifying grease are called surfactants i.e., soap and detergents. Soaps are sodium or potassium salts of long chain fatty acids such as palmitic acid $\left(\mathrm{C}_{15} \mathrm{H}_{31} \mathrm{COOH}\right)$, stearic acid $\left(\mathrm{C}_{17} \mathrm{H}_3 \mathrm{COOH}\right)$ and linolic acid $\left(\mathrm{C}_{17} \mathrm{H}_{31} \mathrm{COOH}\right)$ Potassium salts of fatty acids such as palmitic acid, stearic acid and oleic acid are called soft soap.

Generally, potassium soap are soft to the skin so, they are named as soft soap.