What is the IUPAC name for the molecule with the structure ${\mathrm{CH}}_3\mathrm{CH}-\mathrm{CH}-{\mathrm{CH}}_3$?

• A. $2-\mathrm{methylpropane}$
• B. $\mathrm{butane}$
• C. $\mathrm{isobutane}$
• D. $2-\mathrm{methylbutane}$

Answer: (A)

Verified step by step guidance

1. Identify the longest continuous carbon chain in the molecule. This chain determines the base name of the compound according to IUPAC nomenclature.
2. Number the carbon atoms in the longest chain starting from the end nearest to the substituent (branch) to give the substituent the lowest possible number.
3. Identify and name the substituents attached to the main chain. In this case, look for alkyl groups such as methyl (–CH₃) groups attached to the main chain.
4. Combine the substituent names and their position numbers with the base name of the longest chain. Use hyphens to separate numbers and names, and commas to separate multiple numbers if needed.
5. Write the full IUPAC name by placing the substituent(s) with their position(s) before the base name. For example, if a methyl group is attached to the second carbon of a butane chain, the name would be \$2\text{-}methylbutane$.