According to IUPAC nomenclature, what is the systematic name for the hydrocarbon with the molecular formula $C_5{H}_{12}$?

• A. 2,2-Dimethylpropane
• B. Butane
• C. Pentane
• D. 2-Methylbutane

Answer: (C)

Verified step by step guidance

1. Identify the molecular formula given: \(C_5H_{12}\). This formula corresponds to an alkane because it follows the general formula for alkanes, \(C_nH_{2n+2}\), where \(n=5\).
2. Determine the longest continuous carbon chain in the molecule. Since the formula is \(C_5H_{12}\), the longest chain can have 5 carbon atoms, which corresponds to the parent name 'pentane'.
3. Consider possible isomers of \(C_5H_{12}\). These include straight-chain pentane and branched isomers such as 2-methylbutane and 2,2-dimethylpropane. Each isomer has the same molecular formula but different structures and names.
4. Apply IUPAC nomenclature rules: the parent name is based on the longest chain, and substituents are named and numbered to give the lowest possible numbers. For the straight-chain alkane with 5 carbons and no branches, the name is simply 'pentane'.
5. Compare the options given: '2,2-Dimethylpropane' and '2-Methylbutane' are branched isomers, 'butane' has only 4 carbons, so the correct systematic name for the straight-chain \(C_5H_{12}\) hydrocarbon is 'pentane'.