Answer:trifluoromethanesulfonic acid (CF3SO3H).
Explanation:
The trifluoromethanesulfonic acid (CF3SO3H) has a halogen atom which stabilizes the leaving group by withdrawal of charge from the SO3- moiety. The methanesulfonic acid (CH3SO3H) contains an electron pushing group which tends to destabilize the charge centre. The better leaving group will be the stabilized anion which in this case is trifluoromethanesulfonic acid (CF3SO3H). This typifies the role of stabilizing factors in formation of chemical species.
