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