Question

Decreasing order of stability of $C=C$ bond in the following compound is:

• A. p > q > r
• B. r > q > p
• C. p > r > q
• D. q > r > p

Answer 1

The correct option is A p > q > r

The stability of alkene can be determined by counting the number of $\alpha$ hydrogens. More the number of $\alpha$ hydrogens, more stable will be the alkene.
The $C=C$ bond indicated as p has 10 $\alpha$-H, q has 4 $\alpha$-H, and r has only 1 $\alpha$-H. Therefore, the stability order of the $C=C$ bond is:
p > q > r