See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structure: The molecule shown is a straight-chain compound with a terminal alkene (C=C double bond) on the left end and a hydroxyl group (-OH) on the right end. Counting the carbon atoms: C1=C2-C3-C4-C5-OH gives five carbons total. Step 2 - Determine the parent chain: The longest carbon chain containing both the double bond and the hydroxyl group has 5 carbons, so the parent name is 'pent'. Step 3 - Identify and number the functional groups: There is one C=C double bond and one -OH group. In IUPAC nomenclature for compounds containing both an alkene and an alcohol, the -ol suffix (hydroxyl) gets the lowest possible locant. Numbering from the -OH end: OH is at C1, and the double bond would be at C4-C5. Numbering from the alkene end: double bond at C1-C2, and OH at C5. The -ol group takes priority for lowest locant, so we number from the OH end, giving OH at C1 and the double bond at C4. Step 4 - Construct the IUPAC name: parent chain = pent, double bond at position 4 = pent-4-en, hydroxyl at position 1 = pent-4-en-1-ol. Step 5 - Verify: pent (5C) + 4-en (double bond between C4 and C5) + 1-ol (OH at C1) correctly describes CH2=CH-CH2-CH2-CH2OH. Therefore, the correct answer is pent-4-en-1-ol.