Why a Chest Tube is Placed. A chest tube is placed for a variety of reasons. One reason, as you mentioned, is to help the lung re-inflate when someone has a collapsed lung, also known as a pneumothorax. In that circumstance, a chest tube is inserted along the side of the ribs to allow the lung to reinflate.
A. Osmosis is the passive movement of water from an area high in water concentration, across a semi-permeable membrane, to an area low in water concentration.
While diffusion involves movement of any chemical from one place to another, osmosis involves movement of only water across a permeable membrane. This makes it clear that it is only water that can undergo osmosis. As such it can be said that osmosis is a special type of diffusion.