In reverse osmosis, what is the direction of the water flow, if a container contains two solutions having different concentrations, separated by a semi-permeable membrane?

In reverse osmosis, water flows from a higher concentrated solution to a lower concentrated one by applying pressure greater than the osmotic pressure across a robust semi-permeable membrane.

Explanation:

In reverse osmosis, water flows from a solution with a higher concentration to one with a lower concentration, opposite to that of ordinary osmosis. This is accomplished by applying external pressure greater than the osmotic pressure on the side of the more concentrated solution.

The process requires a robust semi-permeable membrane capable of withstanding the additional pressure while preventing solute molecules from passing through. Reverse osmosis is extensively utilized for water purification, including desalination, producing potable water from ocean or sea water, especially in places where freshwater is scarce.

This occurs when external pressure is applied to the more concentrated solution, exceeding the osmotic pressure. For example, in a container with two solutions of different concentrations separated by a semipermeable membrane, water molecules will move from the more dilute solution to the more concentrated solution.