Chapter 15.1, Problem 15.2PSP

Calculate the ratio of $\left[{\text{HPO}}_4^{2-}\right]$ to $\left[{\text{H}}_2{\text{PO}}_4^{-}\right]$ in blood at a normal pH of 7.40. Assume that this is the only buffer system present. For ${\text{H}}_2{\text{PO}}_4^{-}$, K_a = 6.3 × 10⁻⁸.