Reflux is one of the most common techniques you will encounter in your chemistry laboratory classes. Since many reactions between covalent compounds are slow processes rather than instantaneous reactions, prolonged heating forces the equilibrium to give an acceptable amount of product. In the reflux process, the reactants are dissolved or suspended in a suitable solvent, the solvent is boiled and then condensed so that it returns to the reaction flask. Once set up, a reaction carried out under reflux can be run for minutes, hours or even days to promote the required reaction. The basic components for a reflux apparatus are: