Glass Tubing

U–tube filled with a sodium hydroxide is used for a cleaned and dried gas. U–tube filled with a 1 mol dm^–3 aqueous potassium nitrate solution is used as a permanent salt bridge. U–tube is a device used for water electrolysis, for laboratory hydrogen and oxygen obtaining.

An evaporating dish or watch glass is a piece of laboratory glassware used for the evaporation of solutions and supernatant liquids, and sometimes to their melting point.