Chapter 9, Problem 9.70P

For each pair of acids: $[1]$ Label the stronger acid. $[2]$ Draw the conjugate bases. $[3]$ Label the
stronger conjugate base.
a. $\begin{array}{c}{\text{H}}_3{\text{PO}}_{\text{4}}\\ \text{phosphoric acid}\\ K_a=7.5\times {10}^{-3}\end{array}$ or $\begin{array}{c}\text{HCOOH}\\ \text{formic acid}\\ K_a=1.8\times {10}^{-4}\end{array}$

b. $\begin{array}{c}\text{HCOOH}\\ \text{formic acid}\\ K_a=1.8\times {10}^{-4}\end{array}$ or $\begin{array}{c}{\text{C}}_6{\text{H}}_{\text{5}}\text{COOH}\\ \text{benzoic acid}\\ K_a=6.5\times {10}^{-5}\end{array}$