Step 1: Understand what an alkane is. Alkanes are hydrocarbons that consist only of carbon (C) and hydrogen (H) atoms, with single bonds between the carbon atoms.
Step 2: Know the difference between straight-chain and branched alkanes. Straight-chain alkanes have all carbon atoms connected in a single line, while branched alkanes have one or more carbon atoms connected to the main chain.
Step 3: Identify the alkanes in the question: butane, pentane, hexane, and isobutane.
Step 4: Draw or visualize the structure of each alkane. Butane has 4 carbon atoms in a straight line. Pentane has 5 carbon atoms in a straight line. Hexane has 6 carbon atoms in a straight line. Isobutane has 4 carbon atoms, but one of them branches off the main chain.
Step 5: Determine which alkane is branched. Isobutane has a branch, while butane, pentane, and hexane do not.
