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.