Question

$1,3,5,7-$ Octatetraene contains $\underset{–}{X}$ $\sigma -$ bonds and $\underset{–}{Y}$ $\pi -$ bonds. $X$ and $Y$ are:

• A. $23,4$
• B. $17,4$
• C. $18,5$
• D. $33,2$

Answer 1

Answer: (B)

$17,4$

A $\sigma$ bond is a type of covalent bond. It is formed by the head-on overlap of two atomic orbitals. These combinations of overlapping orbitals will be as $s-s,s-p_{z}or{p}_z-p_z$.

Also, a $\pi$ bond is also a covalent bond. It is formed by the side-to-side overlap of two atomic orbitals. The atomic orbital may have combinations as $p_x-p_{x}or{p}_y-p_y$

Thus as in the figure, total $\sigma$ bonds will be 17 and $\pi$ bonds will be 4.

Thus option B is correct.