How many sigma and pi bonds are present in a molecule of ${\text{C}}_2{\text{H}}_4$?

Solution

1. The structure of ethene is ${\text{CH}}_2={\text{CH}}_2$.
2. There are four $\text{C-H}$ sigma bonds and one $\text{C-C}$ sigma bond, totaling 5 sigma bonds.
3. The double bond consists of one sigma bond and one pi bond.
4. Hence the answer is (A).