Question

Which of the following species contains equal number of σ– and π–bonds?

Options

• \[\ce{HCO^-_{3}}\]

• XeO₄

• (CN)₂

• CH₂(CN)₂

Answer 1

XeO₄ 

Explanation:

The following are the species' Lewis structures:

\[\begin{array}{cc}
\phantom{.}\ce{:O:}\\
\phantom{.}||\\
\phantom{}\ce{H - \overset{\bullet\bullet}{\underset{\bullet\bullet}{C}} - \underset{\underset{1 π bond}{4 σ bonds}}{C} - \overset{\bullet\bullet}{\underset{\bullet\bullet}{O}}:^-}
\end{array}\]

\[\begin{array}{cc}
\phantom{}\ce{:O:}\\
\phantom{}||\\
\phantom{}\ce{Xe}\\
\phantom{}//\phantom{...}||\phantom{...}\backslash\backslash\\
\phantom{}\ce{:O:}\phantom{.}\ce{\underset{\underset{1 π bonds}{4 σ bonds}}{:O:}}\phantom{.}\ce{:O:}
\end{array}\]

\[\ce{\overset{\bullet\bullet}{N} = \underset{\underset{4 π bonds}{3 σ bonds,}}{C - C} ≡ \overset{\bullet\bullet}{N}}\]

\[\begin{array}{cc}
\ce{H}\phantom{.....}\\
|\phantom{.....}\\
\phantom{}\ce{H - C - C ≡ \overset{\bullet\bullet}{N}}\\
|\phantom{.....}\\
\phantom{}\ce{\underset{\underset{4 π bonds}{6 σ bonds,}}{C ≡ \overset{\bullet\bullet}{N}}}
\end{array}\]