The biocarbonate buffer system is present in blood. It consists of a mixture of carbonic acid (H2CO3) and bicarbonate (HCO3-). This buffer system is slightly more complicated than others, because the carbonic acid is formed from dissolved CO2 and water, so both of those equilibria have to be considered in the determination of the pH. Not only does this allow for blood buffering, but it's a system for the body to transport CO2 from cells to the lungs for release. (see p. 61-63 in the text for help with this question).

(a) Write the overall reaction from CO2 to bicarbonate by writing the two described reactions above and cancelling out common terms.

(b) Write the equilibrium constant from the reaction in (a), then derive a Hendersen-Hasselbalch equation from the equilibrium expression. Remember that [H2O] is constant.

(c) The pK value of the system is 6.1. If the [CO2] is expressed in terms of partial pressure and equals 1.3kPa and the bicarbonate concentration is 2.2 x 10^-3 M, what is the pH of the solution.