The osmotic pressure of 0.100 M of KI solution of 25° C is 0.465 atom. Determine the experimental van't Hoff factor for KI at this concentration

Answer 1

osmotic pressure = π = iMRT

π = 0.465 atm

i = van't Hoff factor

M = molarity = 0.100 M

R = gas constant = 0.0821 Latm/Kmol

T = temperature in Kelvin = 298K

Solving for i, we have...

π / MRT = i

i = (0.465 atm) / (0.100 mol/L)(0.0821 Latm/Kmol)(298K)

i = 0.19

Check the math, as this seems rather low since theoretical value is 2. Osmotic pressure of 0.455 atm seems low also.