Answer
a. $HClO_{4(aq)}\Rightarrow H^+_{(aq)}+ClO_{4(aq)}^-$
b. $CH_3CH_2CO_2H_{(aq)}\Rightarrow H^+_{(aq)}+CH_3CH_2CO_{2(aq)}^-$
c. $NH_{4(aq)}^+\Rightarrow H^+_{(aq)}+NH_{3(aq)}$
Work Step by Step
The dissociation of an acid is as follows:
$HA\Rightarrow H^+ + A^-$
Therefore, because all three substances are acids the reactions are:
$HClO_{4(aq)}\Rightarrow H^+_{(aq)}+ClO_{4(aq)}^-$
$CH_3CH_2CO_2H_{(aq)}\Rightarrow H^+_{(aq)}+CH_3CH_2CO_{2(aq)}^-$
$NH_{4(aq)}^+\Rightarrow H^+_{(aq)}+NH_{3(aq)}$
