Osmotic Pressure Formula – Equation and Problem Solved with Example

Osmosis process allows solvent to pass through the semipermeable membrane bot the solute. The pressure is targeted from solvent to solution or weak solution to the concentrated ones. A plenty of practical examples like purifying sea water, industrial extraction or purification, or pure water at home are the result of osmotic process only. This is majorly defined as the selective separation aspect by industries.
Osmotic Pressure Formula

Now, let us discuss on osmotic pressure. This is the excessive pressure applied to solution to avoid osmosis during separation of solvent via semipermeable membrane. The symbol ‘π’ is used to demote the osmotic pressure in Chemistry or Physics. Based on the Van’t Hoff’s law, the osmotic pressure could be defined as the
\[\ \pi = iRTC \]

Where, i denotes the total number of ions created by dissolving solute molecules, R is the ideal gas constant, T is the absolute temperature, C is the molar concentration. One more formula for osmotic pressure that connects osmotic pressure with temperature and volume is very much similar to ideal gas equation and it could be written as –

\[\ \pi = nRV \]
\[\ \pi = MRT \]
Where,
M = the molar concentration of the solution
R = the gas laws constant (0.0821 )
T = the Kelvin temperature

Hence this is clear from the discussion that two solutions of different concentration can be separated by semipermeable membrane in osmotic pressure. The solution with lower concentration can pass through quickly and the solution with higher concentration will be separated. The process will continue until the concentration of both the solution does not gets the same. The concept is necessary to learn by students because it is frequently used in real-life applications.