Rotation from Sigma and Pi bonds

[Rian Montagh 2K]

Why can atoms with sigma bonds rotate, but a pi bond will not allow it to rotate?

[Anand Narayan 1G]

Sigma bonds have their electron density along the bond axis, while pi bonds have their electron density above and below the bond axis. Therefore, pi bonds cannot rotate the same way as sigma bonds since rotation would break the pi bond interaction.

[Ibrahim Malik 1H]

The condition for double bonds is to be stable and rigid. A combination of a pi and sigma bond (forms a double bond) has restrictions on how the bond can rotate. If this bond rotates past its range of motion, the double bond would break.