Question

3. The principle equilibrium in a solution of NaHCO3 is HCO + HCO ) -> H,CO3aq) + CO2(aq) a) Calculate the value of the equilibrium constant for this reaction. b) What is the relationship between [H2CO3] and [CO3 ?) at equilibrium? What assumption did you make in arriving at this conclusion? c) Using the equilibrium H2CO3(aq) 2H+ (aq) + CO32- (aq) and the result from part (b), derive an expression for the pH of the solution in terms of Kai and Ka2. d) What is the pH of a solution of NaHCO3(aq)?

give answer in terms of concentration, such as [H2CO3]

no need for actual values

Answer 1

The given beaction is +603 + HCO3 H2CO3 +603 (concentration of product [concentration of reactants J. The equilibrium constant for this ran is keg Oncos Co3-) [Heos (Hoz) in Multiply nimemalator Ę denominator by Crt] keq. Czloz] (63) Cat] CHccs] Coros CAT] Rearranging above equation - CAT] (co? - ] [H26os) [Acog] (47] keq- kai tos " =lo 1x10. to 3x107 ka = 4.3x107 kaz I for Hilos keg= loxio & ka = 1.88101 for H2CO3) given: H₂CO3], Clo3? -] To find relationship between the above The deaction in previous part comes to be a principal equilibrium reaction As a result [+2 203] = [603 )

given H₂CO3 (ag) 2 (aq) + Cas (aq) who una alt Checos] [cost] PH of Solution in terms of kai & kan keq - Crty (cos ) kakkor CH2CO3 ] Sluce Chicos) = (com] ie w xva, - сн") - log cut ) - - bag (leihez)he] to purpurned pH phan token 8.31 is the ph of Natt og