Question

Assertion : Sigma $(\sigma )$ is a strong bond, while pi $(\pi )$ is a weak bond.
Reason : Atoms rotate freely about $pi(\pi )$ bond.

• A. If both assertion and reason are true and reason is a correct explanation of the assertion
• B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
• C. If the assertion is true but the reason is false
• D. If both the assertion and reason are false

Answer 1

Answer: (C)

Sigma bonding involves end to end overlapping of the two atomic orbitals e.g. between $s$ and s, s and $p$ and $p$ and $p$ orbitals.

$Pi$ bonding $(\pi )$ involves sidewise overlapping of the two atomic orbitals e.g. between $p$ and $p$ orbitals.

Overlapping of orbitals is more effective in $\sigma$ bonding than in $\pi$ -bonding. Due to the geometry of overlapping or orbitals, rotation of one atom is not