Question

Write the molecular formula of (i) an alkane (ii) an alkene, and (iii) an alkyne, each having 20 carbon atoms.

Answer 1

(i) An alkane comprising 20 atoms of carbon (n = 20):

$C_n{H}_{2n+2}=C_{20}{H}_{2\times 20+2}=C_{20}{H}_{42}$

(ii) An alkene comprising 20 atoms of carbon (n=20):

$C_n{H}_{2n}=C_{20}{H}_{20\times 2}=C_{20}{H}_{40}$

(iii) An alkyne comprising 20 atoms of carbon (n=20):

$C_n{H}_{2n-2}=C_{20}{H}_{2\times 20-2}=C_{20}{H}_{38}$