Branched Chain Hydrocarbons Explained

A hydrocarbon is described as having a branched chain when one or more carbon atoms are bonded to more than two other carbon atoms. This differs from a straight-chain hydrocarbon, where carbon atoms form a continuous, unbranched sequence.

Analyzing Option Structures

Let's examine the structure of each hydrocarbon option:

• Ethene (C₂H₄): Structure is $CH₂=CH₂$. This is a linear molecule with a double bond, not a branched chain.
• Isobutane (C₄H₁₀): Also known as 2-methylpropane. Structure is $(CH₃)₃CH$. This features a central carbon atom bonded to three methyl ($-CH₃$) groups, clearly indicating a branched chain.
• Butane (C₄H₁₀): The straight-chain isomer is $CH₃CH₂CH₂CH₃$. All carbon atoms are in a continuous line, so it is not branched.
• Methane (CH₄): Structure is $CH₄$. This consists of a single carbon atom, so it cannot have a branched chain.

Conclusion: The Branched Hydrocarbon

Based on the structural analysis, Isobutane is the only hydrocarbon among the options that contains a branched chain structure.