What will be the IUPAC name of the following compound?

The correct answer is Option (3) → 3,7-Dimethylocta-2,6-dienal

For an aldehyde, the longest chain containing the –CHO carbon is chosen and numbered from the aldehyde carbon (C-1):

    \( \mathrm{\overset{1}{C}HO-\overset{2}{C}H=\overset{3}{C}(CH_3)-\overset{4}{C}H_2-\overset{5}{C}H_2-\overset{6}{C}H=\overset{7}{C}(CH_3)-\overset{8}{C}H_3} \)

• Main chain: 8 carbons (one terminal \( \ce{CH3} \) at C-7 is counted as C-8) ⇒ oct

• Double bonds start at C-2 and C-6 ⇒ octa-2,6-diene

• Methyl groups at C-3 and C-7 ⇒ 3,7-dimethyl

• Suffix for the aldehyde: -al (its carbon is C-1, so no locant is written)

Name: 3,7-Dimethylocta-2,6-dienal (the compound is citral).

NCERT (2026-27 edition):
IUPAC Names