Organic synthesis. Reflux apparatus used to make phenylamine. The pear-shaped reaction flask is in a beaker of water to prevent the reaction mixture from overheating. A clamp holds a reflux condenser connected vertically to the reaction flask. To the right-hand side, concentrated hydrochloric acid is contained in the dropping funnel used to add it to the reaction flask containing tin (a catalyst) and nitrobenzene. After the initial reaction, the water bath is heated to boil the reaction mixture and complete the reaction. The vapour is retained by the water-cooled condenser. Phenylamine is used in the manufacture of dyes and medical drugs.