A Liebig condenser is a type of glass condenser commonly used in laboratory distillation processes. It consists of a long straight glass tube, with an outer jacket and an inner tube. Cool water flows through the outer jacket, while the hot vapor passes through the inner tube, where it is condensed back into a liquid. The condensed liquid then flows out of the bottom of the condenser. Liebig condensers are popular due to their simple design and ease of use. They are commonly used for distilling solvents or purifying liquids in the laboratory.