But again since im being asked about which hydrolysis goes faster, shouldn't the electrophilicity of the carbonyl be considered?
chloride is more withdrawing group so logically it will make it a better electrophile ( more positive charge ) no?
But if i compare the basicity of the leaving groups
Cl- / conjugate acid is HCl with a pKa of -6.3 so it has a stronger conjugate acid than CF3COOH so Cl- is a weaker base and hence a better leaving group.
It sort of does depend on which step is rate limiting, I think. If attack at the carbonyl is rate limiting, then it matters more how electrophilic the carbonyl carbon is. If loss of leaving group is rate limiting, then it depends mainly on which leaving group is better. I recall reading that for esters, loss of leaving group is usually rate limiting but it could go either way. For acid chlorides I recall that attack at the carbonyl is rate limiting because chloride is such a great leaving group.
But in the end it doesn't really matter for predicting relative reactivity, because the pKa of the conjugate acid of the leaving group will still predict relative reactivity as an electrophile, regardless of what the rate limiting step is. The pKa is sort of a "nemonic" for predicting the correct answer. Thus you don't really need to know what the rate limiting step is. I guess it works because a more weakly basic leaving group also is more withdrawing toward the carbonyl carbon, prior to leaving.
If anybody has any examples where this turns out not to be true, I would be very curious to hear them!