In a comprehensive study of bond polarity, bond enthalpy, and the resulting reactivity of alkyl hali — Haloalkanes and Haloarenes Chemistry Question
Question
In a comprehensive study of bond polarity, bond enthalpy, and the resulting reactivity of alkyl halides, which of the following scientific statements are fundamentally correct?
💡 Solution & Explanation
A) True. The $C-F$ bond is the strongest ($452$ kJ/mol), making $F^-$ a very poor leaving group despite the extreme polarity of the bond. B) True. The $C-I$ bond is the longest and weakest ($234$ kJ/mol) because a large $5p$ orbital (I) cannot effectively overlap with a small $2sp^3$ orbital (C), making it highly reactive. C) False. If polarity strictly dictated rates, fluorides would be the most reactive, which contradicts experimental evidence. Bond enthalpy is the primary kinetic factor. D) True. Good leaving groups are highly stable anions, which equates to being weak conjugate bases. Since $HI$ is the strongest acid, $I^-$ is the weakest conjugate base and the best leaving group.