Question

write the Molecular formula for 2nd and 3rd member of homologous series whose first member is methane

Answer 1

C2H6 and C3H8 is the answer.

Members of a homologous series differ by -CH2 unit

Answer 2

2nd member of homologous series is

Ethane ( C2H6)

3rd member is

Propane (C3H8)