Solved Chegg Answers
11) Always the sigma bond formation is due to sharing of two electorns between two atoms and which is also called as the covalent bond.
12) Partial overlap between two p orbitals known as pi bond.
Sigma and pi bonds were shown in the above picture.
13) this is question is not visible properly. But taking HCN as an example, it has one sigma and two pi bonds totally.