Question

Write the structural formulae of the following compounds:
(i) Pentanone-3
(ii) 2-Propanol

Answer 1

(i) Pentanone-3
Pentan means that the parent chain has 5 C atoms. The suffix one-3 represents carbonyl group on third C atom.
(ii) 2-Propanol
Propan means that the parent chain has 3 C atoms. The suffix ol represents alcoholic $-OH$ group. The prefix 2 represents that $-OH$ group is on second C atom.