# Will an acyl chloride be attacked by water molecule to form carboxylic acid?

$\ce{H2O}$ molecules can act as a nucleophile. So it should attack the carbonyl carbon. However, I think that that when the $\ce{O-}$ "kicks back" it will once again remove the water molecule keeping the $\ce{Cl}$ intact as water is definitely a better leaving group. But in my book they showed a reaction intermediate, which involved an acyl chloride and they used water molecule as a nucleophile to convert acyl chloride to carboxylic acid. I'm confused as to how that is possible? Isn't water a better leaving group than $\ce{Cl-}$ ?

• Don't really remember, but in general proton transfers are very fast. For mechanistic organic chemistry Clayden is a good place to start. – orthocresol May 13 '17 at 16:25

$$\ce{RCO\color{red}{Cl} + \color{red}{H}OH -> RCOOH + \color{red}{HCl}}$$
so in the absence of a second base, you will necessarily have to produce $\ce{H3O+}$.