Question

Nodal planes of $\pi$-bonds (s) in $C{H}_2=C=C=C{H}_2$ are located in:

• A. all are in molecular plane
• B. perpendicular plane which contains $C-C$ $\sigma$-bond
• C. one in molecular plane and two in a plane perpendicular to molecular plane which contains $C-C$ $\sigma$-bonds
• D. two in molecular plane and one in a plane perpendicular to molecular plane which bisects $C-C$ $\sigma$-bonds at right angle

Answer 1

The correct option is B perpendicular plane which contains $C-C$ $\sigma$-bond

Nodal planes of $\pi$- bonds (s) in ${CH}_2=C=C={CH}_2$
The pi bond is formed perpendicular to the plane in which one lobe of electron density is above the plane and one lobe of electron density is below the plane.
The nodal plane of the pi bond is in between the two lobes of electron density of the pi bond.
So 2 in a molecular plane and 1 in the plane perpendicular to the molecular lane in which has $C-C$ bond.