Question

The stability order of $\pi$ - bond in following alkenes in the increasing order is:
$\underset{\left(I\right)}{C{H}_3-CH=C{H}_2}$

$\underset{\left(II\right)}{C{H}_3-\underset{\underset{C{H}_3}{|}}{C}=\underset{\underset{C{H}_3}{|}}{C}-C{H}_3}$

$\underset{\left(III\right)}{C{H}_3-\underset{\underset{C{H}_3}{|}}{C}=C{H}_2}$

$\underset{\left(IV\right)}{C{H}_3-\underset{\underset{C{H}_3}{|}}{C}=CH-C{H}_3}$

• A. I < III < IV < II
• B. I < II < III < IV
• C. IV < III < II < I
• D. II < III < IV < I

Answer 1

The correct option is A I < III < IV < II

Stability of alkene $\propto$ Number of $\alpha$-H atoms.
Structure (I) has 3 $\alpha$-H, (II) has 12 $\alpha$-H, (III) has 6 $\alpha$-H, and (IV) has 9 $\alpha$-H. Therefore, the stability order of $\pi$-bond in the alkenes is:
I < III < IV < II