\[
\begin{array}{|c|c|c|c|c|c|c|c|}
\hline \text{compound} & \text{important species present} & \text{ionic} & \text{molecular} & \text{strong acid} & \text{weak acid} & \text{strong base} & \text{weak base} \\
\hline \text{HCl} & \mathrm{H}_{3} \mathrm{O}^{+}, \mathrm{Cl}^{-}, \mathrm{H}_{2} \mathrm{O} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✗}} \\
\hline \text{KOH} & \mathrm{K}^{+}, \mathrm{OH}^{-}, \mathrm{H}_{2} \mathrm{O} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✓}} & \boxed{\text{✗}} \\
\hline \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2} & \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}, \mathrm{OH}^{-}, \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{H}_{2} \mathrm{O} & \boxed{\text{✗}} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✓}} \\
\hline \mathrm{HNO}_{2} & \mathrm{H}_{3} \mathrm{O}^{+}, \mathrm{NO}_{2}^{-}, \mathrm{HNO}_{2}, \mathrm{H}_{2} \mathrm{O} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✗}} & \boxed{\text{✓}} & \boxed{\text{✗}} & \boxed{\text{✗}} \\
\hline
\end{array}
\]