Write the molecular formula of the third and fifth members of homologous series of carbon compounds represented by the general formula `C_(n)H_(2n-2)`.

Explanation

The general formula `C_(n)H_(2n-2)` is of the alkyne series . We know that the first member of the alkyne series is ethyne `(C_(2)H_(2))` and it has 2 carbon atoms in its molecule.
(i) Since the first member of alkyne series has 2 carbon atoms in the therefore, third member of alkyne series will have 4 carbon atoms in its molecule . So if we put n=4 in the general formula `C_(n)H_(2n-2)` then the molecular formula of the fifth member of the alkyne series will be `C_(6)H_(2xx6-2)` or `C_(6)H_(10)`.