How many structures are possible for $ {{C}_{5}}{{H}_{8}} $ with one triple bond?
(A) 4
(B) 3
(C) 2
(D) 1

Hint: The atoms can combine or attach to each other by different methods and one of the methods for combining is bonding. The bonding in organic compounds is covalent bonding. There are three different types of bonding and they are single bond, double bond and triple bond. In triple bonds two atoms share three electrons pairs between each other.

Complete step by step answer:
The triple bond is also known as triple covalent bond. ${{C}_{5}}{{H}_{8}} $ is known as pentyne. The structure that can be made of pentyne with one triple bond are:

The first structure made is known as Pent-1-yne. The second structure is known as Pent-2-yne.the third structure which is made is branched so we will see the longest chain of carbon atoms and then name it so the name will be 3 methyl but-1-yne. So the structure that can be made by pentyne is 3. So the correct option for this question is option ’b’. in the first structure we have 12 sigma bonds and two pi bonds. In structure two of pent-2-yne we have again 12 sigma bonds and two pi bonds. In structure three of 3 methyl but-1-yne we have again 12 sigma bonds and two pi bonds.

Note:
Sigma and pi bonds are the chemical covalent bonds which are formed by the overlapping of the atomic orbital. in sigma bonds the end to end overlapping takes place. In pi bond the lobes of the atomic orbital are overlapped.