Which name refers to the branched-chain alkane with formula C4H10?

Which name refers to the branched-chain alkane with formula C4H10?

• A. Butane
• B. Pentane
• C. Methyl propane
• D. Ethane

Answer: (C)

Understanding how alkanes are named helps you spot isomers with the same formula but different structures. For four carbons, there are two possibilities: a straight-chain form and a branched form. The branched one has a methyl group attached to a propane chain, giving a total of four carbons, so its name points to a branch on propane. That structure is best described as methyl propane, which is more precisely 2-methylpropane. This is also known as isobutane. Its formula is C4H10, matching the question’s requirement. In contrast, the straight-chain four-carbon alkane is butane (unbranched), still with the same formula but not branched. The other options refer to different molecules: ethane has two carbons, and pentane has five, so they don’t fit the given formula.

Understanding how alkanes are named helps you spot isomers with the same formula but different structures. For four carbons, there are two possibilities: a straight-chain form and a branched form. The branched one has a methyl group attached to a propane chain, giving a total of four carbons, so its name points to a branch on propane. That structure is best described as methyl propane, which is more precisely 2-methylpropane. This is also known as isobutane. Its formula is C4H10, matching the question’s requirement.

In contrast, the straight-chain four-carbon alkane is butane (unbranched), still with the same formula but not branched. The other options refer to different molecules: ethane has two carbons, and pentane has five, so they don’t fit the given formula.