Question

Which one of the following mono-enes does not exhibit geometric isomerism?

• A. $C_{4}H_{8}$
• B. $C_{3}H_{6}$
• C. $C_{5}H_{10}$
• D. $C_{8}H_{16}$

Answer 1

Answer: (B)

$C_{3}H_{6}$

Answer 2

The main conditions for exhibiting geometrical isomerism are
(i) presence of double bond.
(ii) presence of different groups on same double bonded carbon.
(iii) presence of at least one similar group on adjacent double bonded carbon atoms.
$\therefore C_{3} H_{6}\left(\stackrel{3}{C} H_{3}-\stackrel{2}{C} H=\stackrel{1}{C} H_{2}\right)$
does not exhibit geometric isomerism due to presence of same group on double bonded carbon atom $\left(C_{1}\right)$.