Which of the following alkanes has a straight-chain structure?
A. Cyclopentane (C5H10) B. Isobutane (C4H10) C. 2 - methyl propane (C4H10) D. Pentane (C5H12)
Correct Answer: D
Explanation
Pentane (C5H12) is a straight-chain alkane. Alkanes are hydrocarbons with the general formula CnH2n+2. They are called straight-chain alkanes if all the carbon atoms are connected in a continuous chain without any branches. Butane and Isobutane are both C4H10, but Isobutane has a branched structure, not a straight chain. Cyclopentane (C5H10) is a cycloalkane, not a straight-chain alkane.
