Given a 3D representation of butane, which bond-line (skeletal) structure correctly represents the molecule?

• A. A ring of four vertices forming a square, representing cyclobutane
• B. A straight chain of four connected vertices with no branches, representing $C_4{H}_{10}$
• C. A straight chain of three connected vertices with a branch at the end, representing propane
• D. A branched chain with three connected vertices and a single branch at the central carbon, representing isobutane

Answer: (B)

Verified step by step guidance

1. Identify the molecular formula of butane, which is \(\mathrm{C_4H_{10}}\), indicating a straight or branched chain of four carbon atoms with appropriate hydrogens.
2. Recall that cyclobutane is a ring structure with four carbons connected in a square, which differs from butane's open-chain structure.
3. Understand that a straight chain of four connected vertices with no branches corresponds to n-butane, the unbranched isomer of butane.
4. Recognize that a straight chain of three carbons with a branch at the end corresponds to propane derivatives, which have fewer carbons than butane.
5. Note that a branched chain with three connected vertices and a branch at the central carbon represents isobutane, a branched isomer of butane, distinct from the straight-chain form.