See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the functional group. The structure contains a -C(=O)-OCH3 group, which is an ester (methyl ester). The principal characteristic group is the ester, so the parent chain must end in '-oate' and the alkoxy (methoxy) part is named as 'methyl' prefix. Step 2: Identify the parent acid chain. The carbonyl carbon (C=O of ester) is C1. Attached to C1 is C2, which bears an ethyl substituent (-C2H5). Continuing the chain from C2: C2-C3 (from CH2) and C4 (from CH3), giving a 4-carbon chain including the carbonyl carbon. So the parent chain is butanoate. Step 3: Name the substituent. At C2 of the butanoate chain, there is an ethyl group (-C2H5). This gives the substituent name '2-ethyl'. Step 4: Combine. The ester is a methyl ester (OCH3), parent chain is butanoate, substituent is 2-ethyl. Full name: Methyl 2-ethylbutanoate. Step 5: Reject other options. - (b) 'butanone' implies a ketone, not an ester - incorrect functional group. - (c) '3-Methoxycarbonylpentane' treats the ester as a substituent on pentane; this is not the preferred IUPAC approach when the ester is the principal characteristic group. - (d) 'butanal' implies an aldehyde - incorrect functional group. Therefore, the correct answer is A.