Question

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

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

Answer 1

Answer: (D)

$\%$ S-character $\propto \frac{1}{\text{ Bond length }}$ in (ii) & (iii) , (ii) having ( $+$ ) hyperconjugation so double bond character.