Question

What is correct increasing order of bond lengths of bond indicated as $I,II,III,$ and $IV$ in the following compounds?

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

Answer 1

The correct option is D $IV<I<II<III$

Generally, the triple bond is of short length than double and single bonds. Double bonds are shorter than single bonds.

So, $IV<I$

In between $II$ & $III,III$ is shorter because it is near to triple bond. The triple bond effect bond $III$ and it is shorter than $II$.

$III$ and $II$ are longer than $IV$ & $I$ because, they are single bonds. So order is,

$IV<I<II<III$