Created By : Rina Nayak

Reviewed By : Phani Ponnapalli

Last Updated : Apr 25, 2023

The osmotic pressure calculator analyzes the amount of pressure required to completely halt the osmosis. To get the osmotic pressure of the solution as output , we need to give input i.e the values of numbers of ions,osmotic coefficient, concentration of the solution, temperature and then click the calculate button to obtain the result.

Number of ions
Osmotic coefficient
Osmotic pressure

Osmotic Pressure- Definition

Osmotic pressure is defined as the pressure that is applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution. Osmosis is defined as the movement of solvent from a region of lower solute concentration to a region of higher solute concentration through a semipermeable membrane.

Osmotic Pressure Formula

The formula for osmotic pressure is given as, π = n ჶ c R T

  • Here, π = the osmotic pressure , its unit is pascals (pa)
  • n = the number of ions produced when solute dissociation.also called the dissociation factor or van’t Hoff factor.
  • ჶ = is the solute osmotic coefficient
  • C = is the molar concentration of the solutionv
  • R = is the universal gas constant ,its value is 8.134J(K-mol)
  • T = is the temperature on the kelvin scale.

How to find Osmotic Pressure?

Follow the step by step process listed below to determine the osmotic pressure of a chemical solution manually. They are along the lines

  • List out the values of dissociation factor, osmotic coefficient of the solute, solution molar concentration, universal gas constant and temperature initially.
  • Next step is to make sure all of them are in same units of measurements.
  • Obtain the product of all the values listed.
  • The product obtained is nothing but the osmotic pressure.

Osmotic Pressure Examples

Question 1: The osmotic pressure of a potassium chloride solution (at 300K) is 50 atmospheres. What is the molar concentration of potassium chloride in this solution?

Given that,

π the osmotic pressure = 50atm

Temperature T = 300K

the number of ions n = 2

osmotic coefficient ჶ = 0.0821

universal gas constant R = 8.341J

The formula for osmotic pressure is given as,

π = n ჶ c R T

Substitute in the formula, the given values

π = n ჶ c R T

c = π / (n ჶ R T)

= 50 / ( 2 * 0.0821 * 8.314 * 300 ) = 50/49.26

= 1.015 M

Therefore, the molar concentration of the potassium chloride is 1.015M.

Question 2: One mole of table salt is dissolved into water of volume of one liter, at a temperature of 27 c. Determine the osmotic pressure of this solution?


Given that,

C = 1 mole

i = 2, since Nacl dissociates into 2 ions.

T = 27+273 300K

R = 0.0821 atm L / mol .K universal gas constant

substitute the values in the formula

π = i×C×R×T

pi = 2* 1*0.0821*300 = 49.26atm

Thus ,the osmotic pressure of the 1M of salt solution will be 49.26atm.

FAQ’s on Osmotic Pressure Calculator

1. What is meant by osmotic pressure?

Osmotic pressure is defined as the pressure that must be applied to the solution side to stop fluid movement when a semipermeable membrane separates a solution from pure water.

2. What is the formula for osmotic pressure?

The formula for osmotic pressure is π = i×C×R×T π = the Osmotic pressure i = is the van’t hoff factor C = is the molar concentration of the solute in the solution R = is the universal gas constant,its value is 8.134J(K-mol) T = the temperature on the kelvin scale.

3. Why is osmotic pressure positive?

Osmotic pressure is a hydrostatic pressure exerted to the solution to prevent the flow of water through the semipermeable membrane. This pressure is generally created by the solute present in the solution. That's why the osmotic pressure of a solution will always be positive.

4. What is osmotic pressure in capillaries?

Osmotic pressure is the"pulling" force on water due to the presence of solutes in solution. Albumin proteins are the main source of osmotic pressure in capillaries, pulling water into the blood.

5. Which has maximum and minimum osmotic pressure?

(NH4)3PO4 will have the highest value of osmotic pressure and Least particles are in glucose solution hence its osmotic pressure is the minimum.