[Chemical name] sodium hydroxide [Chemical formula] NaOH [Common or alternative name] Lye, Caustic Soda [Source and description] 
Grocery, hardware; Known also as caustic soda and lye, sodium hydroxide is used in many commercial drain cleaners/openers. Ex: Rooto Drain Opener (100% Pure), Drano (not 100% pure), Roebic Crystal Drain Opener NB: Keep out of eyes