See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of C–C Bond Lengths **Step 1: Identify the structures and bond types** - $C_2H_6$ (ethane): $C-C$ single bond - $C_2H_4$ (ethene): $C=C$ double bond - $C_2H_2$ (acetylene): $C\equiv C$ triple bond - $C_6H_6$ (benzene): aromatic $C-C$ bonds (between single and double) **Step 2: Apply bond order relationship** Bond length is inversely related to bond order. Higher bond order = shorter bond: $$\text{Bond length: } C\equiv C < C=C < C-C$$ **Step 3: Order the specific molecules** - $C_2H_2$: triple bond (~120 pm) — **shortest** - $C_2H_4$: double bond (~134 pm) - $C_6H_6$: aromatic bonds (~140 pm) — partial double bond character - $C_2H_6$: single bond (~154 pm) — **longest** **Step 4: Verify option (A)** $$C_2H_6 > C_2H_4 > C_6H_6 > C_2H_2$$ $$(154 \text{ pm}) > (134 \text{ pm}) > (140 \text{ pm}) > (120 \text{ pm})$$ ✓ This correctly orders from longest to shortest bond based on bond multiplicity.