See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Carbon-Chlorine Bond Distance Analysis **Key Principle:** Bond distance decreases with increasing bond order and increasing s-character of the bonding orbital. ## Step-by-step comparison: **Option (1): $CH_3-Cl$** - Single bond ($\sigma$) between $sp^3$ carbon and chlorine - Bond distance: ~1.78 Å **Option (2): $C_6H_5-CH_2-Cl$** - Single bond between $sp^3$ carbon (benzyl position) and chlorine - Bond distance: ~1.78 Å **Option (3): $CH_2=CH-Cl$** ✓ - Single bond between $sp^2$ carbon and chlorine - $sp^2$ carbon has **33% s-character** (vs. 25% for $sp^3$) - Greater s-character → shorter bond distance - Bond distance: ~1.71 Å (minimum) **Option (4): $CH_2=CH-CH_2-Cl$** - Single bond between $sp^3$ carbon (allylic position) and chlorine - Bond distance: ~1.78 Å ## Conclusion: The C-Cl bond is **shortest in compound (3)** because the carbon atom directly bonded to chlorine is $sp^2$ hybridized. The increased s-character in $sp^2$ orbitals creates stronger, more contracted bonds compared to $sp^3$ carbons in the other options. **Answer: (3)**