Question

The general molecular formula for the homologous series of alkynes is C_nH_2n−2. Write down the individual molecular formulae of the first, second and third members by substituting the values 2, 3 and 4 respectively for ‘n’ in this formula.

Answer 1

The general molecular formula for the homologous series of alkynes is C_nH_2n−2.

n = 2 C₂H_2×2−2 = C₂H₂ Ethyne

n = 3 C₃H_2×3−2 = C₃H₄ Propyne

n = 4 C₄H_2×4−2 = C₄H₆ Butyne