Carbonic Acid has two pKas: 6.37 and 10.32. The dissociation of H2CO3 can be written as:

Suppose a pure solution of H2CO3 was titrated with NaOH.

a) In the spaces provided indicate at how many OH equivalents would we need to add to have about 100% of carbonic acid (H2CO3), bicarbonate ions (HCO3) or carbonate ions (CO32). Indicate also the net charge of each of these species and the pKa that is related to the first and second equilibria.

b) At how many OH equivalents do we have the point where [H2CO3] = [HCO3]? What is the pH of the solution at this point?

c) At how many OH equivalents do we have the point where [HCO3] = [CO32]? What is the pH of the solution at this point? What is the average charge of all molecules at this point?

d) Which species (H2CO3 or HCO3 or CO32) predominate when the pH is 11?

e) Which species does not exist at concentration at any measurable concentration at pH 5.5?

Please answer all parts and show all work- Thank you!

OH equiv H2CO3HCO3+H+CO32+H+ Charge pKa