Question

During the process of osmosis, the water moves from cell a to b( a with lot of water and b with less amounts of water). But then after water moves from cell a to b, cell a has lesser water than b , so why doesn't the water flow back into cell a?

Answer 1

Osmosis is the process of flow of water from high water concentration to low water concentration through semipermeable membrane. Flow of water takes place until the equilibrium is reached between two systems.

Here, same thing happens, the water from cell a will move into cell b until both cells have equal amount of water. No extra movement of water will occur from a to b. However, in reality during diffusion/osmosis of any liquid or gas, the equal number of molecules are exchanged between two system in contact after equilibrium.