Identify the correct stability order of following alkenes. I) $\left(\mathrm{CH}_3\right)_2…
Identify the correct stability order of following alkenes.
I) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{C}\left(\mathrm{CH}_3\right)_2$
II) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{CH}_2$
III) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{CHCH}_3$
III $\gt$ II $\gt$ I
I $\gt$ III $\gt$ II
II $\gt$ I $\gt$ III
I $\gt$ II $\gt$ III
Solution
The alkene that has greater number of alkyl groups attached to doubly bonded carbon atoms is more stable than other alkenes.
$\therefore \quad$ Order of stability of alkenes with respect to Saytzeff rule is:
$\begin{aligned}
& \left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{C}\left(\mathrm{CH}_3\right)_2\gt\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{CH}\left(\mathrm{CH}_3\right)\gt \\
& \left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{CH}_2
\end{aligned}$