Question

5) A semi-permeable membrane is used to separate pyruvic acid from an aqueous solution of 0.1 mg/L pyruvic acid solution. a) Calculate the osmotic pressure expected in the solution, if pyruvic acid completely dissociates. b) Calculate the osmotic pressure expected in the solution if pyruvic acid does not dissociate. c) What is the pka of the solution if the observed osmotic pressure of the solution is 4920 Pa. (hint: Use the values from a and b to estimate the dissociation constant of pyruvic acid) Temperature = 298 K

Answer 1

(5) we know domotic fressure iCRT... () where, is van't Hoff factor Number of particles for dissociation - Number of particles before disociation Molar concentration R-Gen constant = 0.0821 Laton Ta Tanberrature in Kelvin (a) here, for full disociation of pyruvicond HC - G-coot - Ht the coo from molecule 2 particles will be generated. nolik 0 . 12, 2 holar man Of purovic acid = 88 06 g mol - 0.081 a arm mook T- 2980 ca o inghe = a land of = 1356X10-3 mol/l

using eanation(i) - 2x 1.1356 15 , x 0.087 4 an 298k4 = 5.55 41005 atm in osmotic fororsure of expected solution is 5.55 xlors atm fe) when pyruvic acid doesn't dissociate then i=1 lats Xark using cansations) - 1x 1.1356x10-6 in 2 x v 0.0821 ol - 2.78 x15 atm . when Byrusie and does not dissociate them annotic Pressure is 278x18 5 atm 1:1 Pa= 9.8 69 xroob atm. . 4920u = 9.869 xygro xorb arm = 0.04856 atom here we have to find out the value of i vaung cananions) 0.048 56 aston- i x 1.1356x10 mo. 0.04856 1.1356x10-6 X 0.0821 X299 - 1748 o xoolestaban mo I think the pressure can not be 49 20 fa. Bleanse i can be maximum 2 not yr. So, frease check the date.