Question

write the molecular formula of the 2nd and 3rd member of the homologous series. where the first member is ethyne ​

Answer 1

Propyne and Methyne is the answer

Answer 2

The members of homologous series differ by CH2.

If the first member is ethyne i.e C2H2

Then 2nd member will be C3H4 (propyne)

And 3rd member will be C4H6 (butyne).

Hope it helps.