Ethane's bonds and classification error

Steps:

• Determine ethane's formula: C₂H₆, with structure H₃C-CH₃.
• Count bonds: 1 C-C single bond + 6 C-H single bonds = 7 single covalent bonds total.
• Classify ethane: Alkane (CₙH₂ₙ₊₂), saturated hydrocarbon with only single bonds.
• Identify mismatch: Statement B calls alkanes unsaturated, which applies to compounds with double or triple bonds.

Why B is correct:

• Alkanes are defined as saturated hydrocarbons per IUPAC nomenclature; unsaturated refers to alkenes/alkynes with multiple bonds.

Why the others are wrong:

• A: Bond count matches exactly—7 single covalent bonds in ethane.
• C: Equation balances atoms (C:2, H:6, O:7 on both sides when written as C₂H₆ + ³/₂O₂ → 2CO₂ + 3H₂O); 3O₂ is a common shorthand but technically 3.5.
• D: Free radical chlorination of ethane substitutes one H with Cl, forming C₂H₅Cl.

Final answer: B