See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Concept: IUPAC nomenclature of substituted benzene rings containing a hydroxyl group uses 'phenol' as the parent name (benzenol), with the OH-bearing carbon assigned position 1, and substituents numbered to give lowest locants. Step 1: Identify the structure. The compound is a benzene ring with an OH group and two methyl groups at the ortho positions relative to OH (i.e., on both carbons directly adjacent to the carbon bearing OH). Step 2: Assign the parent name. When OH is present on a benzene ring, the parent chain is 'phenol' or systematically 'benzenol'. The carbon bearing OH is C-1. Step 3: Number the ring. With OH at C-1, the two methyl groups are at C-2 and C-6 (both ortho positions). This gives the lowest possible locants for the substituents. Step 4: Construct the name. The compound is 2,6-dimethylbenzenol (or 2,6-dimethylphenol). The IUPAC systematic name is 2,6-Dimethyl benzenol. Why other options fail: - (a) 1,3-Dimethyl phenol: incorrect positions; 1,3 would place methyls at meta positions, not ortho. - (b) 1-Hydroxy-2,6-dimethyl benzene: not the preferred IUPAC format; OH should be expressed as the principal characteristic group giving 'benzenol' suffix, not as a prefix 'hydroxy' when it is the principal group. - (d) 2-Hydroxy-1,3-dimethylbenzene: treats methyl as the principal group at C-1, but OH has higher seniority and should be at C-1; also the numbering is inconsistent with lowest locant rule when OH is principal group. Option (c) 2,6-Dimethyl benzenol correctly names the compound with OH as the principal characteristic group (suffix -ol, parent benzenol), OH at C-1, and methyl groups at C-2 and C-6. Therefore, the correct answer is C.