NEET (UG) 2024 — Question 63

A tertiary carbon is one that is bonded to three other carbon atoms. For $\ce{C6H14}$, draw each isomeric structure and count the carbon types. n-Hexane: $\ce{CH3-CH2-CH2-CH2-CH2-CH3}$ has no tertiary carbon. 2-Methylpentane: $\ce{CH3-CH(CH3)-CH2-CH2-CH3}$ has only one tertiary carbon (C-2). 2,3-Dimethylbutane: $\ce{CH3-CH(CH3)-CH(CH3)-CH3}$ has two tertiary carbons (C-2 and C-3). 2,2-Dimethylbutane: $\ce{CH3-C(CH3)2-CH2-CH3}$ has a quaternary carbon and no tertiary carbon. Therefore, the compound with two tertiary carbons is 2,3-dimethylbutane, option C.