Pyridine + HCL is the hydrochloride salt of pyridine, a basic six-membered heterocyclic ring. This is the production of erythromycin as one of raw materials. This is used in dehalogenation reactions and can be used as a base in condensation reactions. This is mainly used for pharmaceutical intermediates, biochemical research, organic synthesis. Pyridine + HCL is not soluble in dichloromethane. In the air easily hygroscopic and watery, with pyridine smell.