Question

The central carbon-carbon bond in $1,3-butadiene$ is ____ than that of n-butane.

• A. shorter
• B. longer
• C. equal
• D. none

Answer 1

Answer: (A)

shorter

$Buta1-3-diene$, i.e.,${CH}_2=CH-CH={CH}_2$ has ${sp}^2-{sp}^2$ (CC) bond. The s character is 33.3 % in $1,3-butadiene$ and 25.0 % in n-butane. More is s-character in hybridization, lesser is bond length. Hence, the central carbon-carbon bond in $1,3-butadiene$ is shorter than that of n-butane.