Question

The correct order of decreasing $H-C-H$ angle in the following molecules is

• A. $I>II>III$
• B. $II>I>III$
• C. $III>II>I$
• D. $I>III>II$

Answer 1

Answer: (B)

$H-C-H$ bond angle is about $120^{\circ }$, when $C$ is bonded through a double bond but in case of $C{H}_4$, the $H-C-H$ bond angle is only $109^{\circ }28^{\prime }$. Cyclic compounds have a $H-C-H$ bond angle greater than $109^{\circ }28^{\prime }$ due to hindrance. Thus, the correct order of $H-C-H$ bond angle is $II>I>III$