The table below shows data for the ${{K_{\text{a}}}}$ and ${{\text{p}}{K_{\text{b}}}}$ values for some acids and bases at 298 K.

Which two formulas represent the weakest acid and the weakest base in the table?

A.     HClO and ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{N}}{{\text{H}}_{\text{2}}}$

B.     ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{COOH}}$ and ${\text{N}}{{\text{H}}_{\text{3}}}$

C.     ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{COOH}}$ and ${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{N}}{{\text{H}}_{\text{2}}}$

D.     HClO and ${\text{N}}{{\text{H}}_{\text{3}}}$

A

It was thought “good to mix the data types, ${{\text{p}}{K_{\text{a}}}}$ and ${{K_{\text{a}}}}$”. This was the fifth hardest question (60.81% correct) with the wrong answers almost equally chosen.