QUESTION 2.41
Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K2SO4 in 2L of water at 25∘C, assuming that it is completely dissociated.
Amount of K2SO4 dissolved = 25 mg = 0.025g
Volume of solution = 2L
T=25∘C=25+273K=298K
Molar mass of
K2SO4=(2×39)+(32)+(4×16)=174 g mol−1
Since, K2SO4 dissociates completely as
K2SO4aq−→2K++SO2−4
Total ions produced after dissociation (per mole) = 3
So, i = 3, π=iCRT=i×nVRT=i×W×R×TM×V
=3×(0.025g)×(0.0821 L atm K−1 mol−1)×(298K)(174 g mol−1)×(2L)
=5.27×10−3 atm