How do you denote a cyclohexane with a methyl group at carbon 1?

To denote a cyclohexane with a methyl group at carbon 1, the correct nomenclature uses the format "1-Methylcyclohexane." In this system, the "1-" indicates the position of the methyl substituent on the cyclohexane ring. Although in many cases, the "1-" is often assumed and may be omitted since it's the base position, including it clarifies the structure, especially when there are other substituents present that require numbering for clarity. This nomenclature follows the IUPAC conventions, ensuring precise communication of the molecule's structure.

In contrast, "2-Methylcyclohexane" would imply that the methyl group is attached to the second carbon of the cyclohexane ring, which is not what the question specifies. "Cyclohexylmethane" describes a different structure altogether, referring to a cyclohexane ring with a -CH2-CH3 (ethyl) group attached instead of a methyl group. Finally, "Methylcyclohexane" lacks specificity regarding the position of the methyl substituent, which could lead to confusion about the exact structure being referred to, even though it suggests a methyl substitution on cyclohexane. Therefore, "