Reverse Osmosis : Its Definition and Working MCQ - Practice Questions with Answers

• The term ‘osmotic pressure’ was coined by Pfeffer.
• It is the pressure which is applied at the solution side to prevent the movement of solvent particles towards the solution.
• The osmotic pressure is equal and opposite to the force applied by the solvent particles.
• It can be defined as the excessive hydrostatic pressure which must be applied to the solution in order to make its water potential equal to that of pure water.
• In other words, it is the pressure which is needed to check the process of osmosis.
• It can be measured by osmometer.
• It is a positive force.
• It is a colligative property.
• It is represented by π (pie).
• It is given by:
• π = CRT
  • C is the concentration of the solution in mole per litre
  • R is the Gas Constant
  • ​​​T is the temperature in Kelvin
• Hence, more the C of the solution, more will be the solutes and greater will be the endosmosis. So, more osmotic pressure will have to be applied.
• As the temperature is raised, more amount of osmotic pressure will have to be applied.

Reverse Osmosis

• Reverse osmosis occurs when a large amount of osmotic pressure is applied to the solution such that the pure solvent is pushed out of the solution.
• This technique is used for the purification of water so that pure water is obtained from a solution of water and impurities.