See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structure from the drawing: The image shows a molecule with an NH2 group attached to a carbon. Reading the connectivity: there is an ethyl group (CH3-CH2-) on one side of the NH2-bearing carbon, and on the other side a carbon bearing a methyl group (CH3) and another methyl group, i.e., an isopropyl-type fragment. This gives the full chain: CH3-CH2-CH(NH2)-CH(CH3)-CH3. Step 2 - Count the carbons and number the chain: The longest continuous carbon chain containing the NH2 group is: C1(CH3)-C2(CH(CH3))-C3(CH(NH2))-C4(CH2)-C5(CH3), which is a five-carbon (pentane) backbone. Wait, let us re-examine: CH3-CH2-CH(NH2)-CH(CH3)-CH3. The longest chain is 5 carbons: C1-C2-C3-C4-C5 where C3 has NH2 and C2 has a methyl substituent... Actually numbering to give the NH2 the lowest locant: numbering from the right: C1=CH3, C2=CH(CH3), C3=CH(NH2), C4=CH2, C5=CH3 gives amine at C3 and methyl at C2. Numbering from the left gives amine at C3 and methyl at C4 — so we choose the direction giving lower locants: C1(CH3)-C2(CH(CH3))-C3(NH2)-C4(CH2)-C5(CH3) giving 3-amine and 2-methyl. Step 3 - Apply IUPAC nomenclature: The parent chain is pentane (5 carbons). The amino (-NH2) group is at position 3, and a methyl substituent is at position 2. The compound is therefore named 2-methylpentan-3-amine. Step 4 - Confirm: The structure CH3-CH(CH3)-CH(NH2)-CH2-CH3 matches exactly a pentane chain with a methyl at C2 and an amine at C3. Therefore, the correct answer is 2-methylpentan-3-amine.