Question

Carbon-Carbon double bond in an alkene consists of:

• A. one weak sigma $\left(\sigma \right)$ bond due to head-on overlapping of $s{p}^2$orbitals and one weak pi $\left(\pi \right)$ bond
• B. one weak sigma $\left(\sigma \right)$ bond due to head-on overlapping of $s{p}^3$orbitals and one weak pi $\left(\pi \right)$ bond
• C. one strong sigma $\left(\sigma \right)$ bond due to head-on overlapping of $s{p}^2$orbitals and one weak pi $\left(\pi \right)$ bond
• D. one strong sigma $\left(\sigma \right)$ bond due to head-on overlapping of $s{p}^3$orbitals and one weak pi $\left(\pi \right)$ bond

Answer 1

The correct option is C one strong sigma $\left(\sigma \right)$ bond due to head-on overlapping of $s{p}^2$orbitals and one weak pi $\left(\pi \right)$ bond

Sigma bonds are formed by head-on overlap so they are strong bonds.
pi bonds are formed by lateral overlapping so they are weak bonds.
In alkene, one 's' orbital and two 'p' orbitals of carbon combine to form $\left(s{p}^2\right)$ hybridised orbitals in which one is involved in head-on overlap to give sigma bond and the unhybridised 'p' orbital of adjacent carbons will overlap laterally to form pi bond.
Thus, option (c) is correct.