1 用于制气实验 1.实验室在运用排气法集气时为避免瓶外空气流动影响集气,常在集气瓶口加一棉团。 2.用高锰酸钾制氧时为避免高锰酸钾微粒随气流进入集气瓶中,常在大试管的胶塞里加一棉团。 3.制乙炔时,为避免反应产生的泡沫由导气管喷出,常在大试管的塞下加一膨松棉团。 1 for gas production experiments 1. The laboratory in the use of exhaust gas collection method in order to avoid air flow outside the bottle affect the gas collection, often in the gas bottle mouth plus a cotton ball. 2. When oxygen is produced with potassium permanganate, to prevent the potassium permanganate particles from entering the gas collection bottle with the gas flow, a cotton ball is often added to the rubber plug of the large test tube. 3. When making acetylene, in order to prevent the foam generated by the reaction from being ejected by the air pipe, a bulk cotton lump is often added under the plug of a large test tube.