Question

Write the homologous series of alkynes?

Answer 1

Homologous series means the group of compounds in which there is the same functional group like hydroxyl group, ketone group, carboxylic group, etc. Alkynes are those compounds in which there is at least one triple bond present.

Complete step-by-step answer: In organic compounds, there are several compounds that are classified into groups or families which are based on the functional group present in the compound. Homologous series means the group of compounds in which there is the same functional group like hydroxyl group, ketone group, carboxylic group, etc.
There are some conditions that are fulfilled by each and every member of the family.
Alkynes are those compounds in which there is at least one triple bond present. The general formula is ${{C}_{n}}{{H}_{2n-2}}$ where n is an integer, so the alkynes are only made up of carbon and hydrogen atoms and it is distinguished by the triple bond. These compounds are named with yne in the past.
The first member of the alkyne homologous group is ethyne whose formula is ${{C}_{2}}{{H}_{2}}$ and its structure is $CH\equiv CH$.
The second member of the alkyne homologous group is propyne whose formula is ${{C}_{3}}{{H}_{4}}$ and its structure is $C{{H}_{3}}-C\equiv CH$.
The third member of the alkyne homologous group is butyne whose formula is ${{C}_{4}}{{H}_{6}}$ and its structure is $C{{H}_{3}}-C{{H}_{2}}-C\equiv CH$.
The fourth member of the alkyne homologous group is pentyne whose formula is ${{C}_{5}}{{H}_{8}}$ and its structure is $C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-C\equiv CH$. And so on.

Note: Other homologous series like alkanes having a formula ${{C}_{n}}{{H}_{2n+2}}$, alkene having a formula ${{C}_{n}}{{H}_{2n}}$, carboxylic acid having formula ${{C}_{n}}{{H}_{2n+1}}COOH$, etc. All the members of the group have similar method preparation.