Exercise 5 | Covalent Bonding

How many σ and π bonds are there in the following molecules:
 

single bond = 1 σ bond

double bond = 1 σ + 1 π bonds

triple bond = 1 σ + 2 π bonds

 

Molecule A
single bonds: 3 C-C + 6 C-H ⇒ 9 σ bonds
double bonds: 3 C-C ⇒ 3 σ bonds + 3 π bonds
Total: 12 σ bonds + 3 π bonds
 

Molecule B
single bonds: 2 C-C + 2 C-H ⇒ 4 σ bonds
double bonds: 2 C-O ⇒ 2 σ bonds + 2 π bonds
triple bond: 1 C-C ⇒ 1 σ bond + 2 π bonds
Total: 7 σ bonds + 4 π bonds
 

Molecule C
single bonds: 6 C-C + 9 C-H ⇒ 15 σ bonds
double bonds: 2 C-C ⇒ 2 σ bonds + 2 π bonds
triple bond: 1 C-N ⇒ 1 σ bond + 2 π bonds
Total: 18 σ bonds + 4 π bonds