Question

According to the Valence bond theory, which statement is incorrect regarding bonding between two carbon atoms?

• A. A sigma( $\sigma$ ) bond is weaker than a Pi $(\pi )$ - bond
• B. A sigma bond is stronger than a Pi bond.
• C. A double bond is stronger than a single bond
• D. A double bond is shorter than a single bond

Answer 1

Answer: (A)

A $\sigma -$ bond is stronger than a $\pi -$ bond. Sigma $\sigma$ bonds are formed by head-on overlap of unhybridised $s-s,p-p$ or $s-p$ orbitals and hybridized orbitals $sp,s{p}^2,s{p}^3,s{p}^{3}d$ and $s{p}^3{d}^2$. Hence, $\sigma$ bond are strong bonds. Where as $Pi\pi -$ bonds are formed by sidewise overlap of unhybridised $p$ and $d$ orbitals. Hence $\pi$ bonds are weak bonds.