See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structure: The molecule is a cyclohexane ring. One carbon bears two methyl groups (gem-dimethyl substitution) and the adjacent carbon bears an ethoxy group (OEt = OCH2CH3). Step 2 - Apply IUPAC numbering rules: The principal characteristic group here is the ether (ethoxy), but for naming purposes we treat the ring carbons by giving the lowest possible locants to all substituents. We must number the ring so that the set of locants is lowest. The two methyl groups are identical substituents on one carbon, and the ethoxy is on the adjacent carbon. Step 3 - Assign locants: Assign C1 to the carbon bearing the two methyl groups (two methyls = 1,1-dimethyl) and C2 to the carbon bearing the ethoxy group. This gives locants {1,1,2} for the substituents. Alternatively, assigning C1 to the ethoxy carbon gives locants {1,2,2}, which is the same set but the first point of difference: comparing {1,1,2} vs {1,2,2}, at the second locant 1 < 2, so {1,1,2} is lower. Therefore C1 = gem-dimethyl carbon, C2 = ethoxy carbon. Step 4 - Construct the name: Base name = cyclohexane. Substituents in alphabetical order: ethoxy (at C2), dimethyl (at C1,C1). Name = 2-ethoxy-1,1-dimethylcyclohexane. Step 5 - Evaluate options: (a) 1-Ethoxy-2,2-dimethylcyclohexane - places ethoxy at C1 and methyls at C2,C2, giving locant set {1,2,2} which is higher than {1,1,2}. Incorrect. (b) 2-ethoxy-1,1-dimethylcyclohexane - matches our derived name exactly. Correct. (c) 1,1-Dimethyl-2-ethoxycyclohexane - same connectivity as (b) but the name format lists dimethyl first; this is actually the same compound but option (b) uses strict alphabetical ordering (ethoxy before dimethyl) per IUPAC, making (b) the better/standard form. However, the locants in (c) are correct; (b) is still the conventionally preferred listing. (d) 2-methyl-1,1-ethoxycyclohexane - incorrect substituent description (ethoxy cannot be 1,1). Therefore, the correct answer is B.