What is the order of acidic strength in O- Fluoro Phenol, m-Fluoro Phenol and p-Fluoro Phenol ? Please specify whether Ortho effect is considered in o-Fluoro phenol or not.
The answer is
O-chlorophenol > o-bromophenol > o-iodophenol > o-fluorophenol
That's because, in o-fluorophenol fluorine is highly electronegetive, forming H- bond with the H atom of OH group. So the acidic nature of this OH is lowest.
In the other three cases, the electro negativity is not so significant compared to F, so here we should look for -I effect of the halogens.
Cl>Br>I, in terms of electro negativity and thus in terms of -I effect also.
Hence the answer.
Ortho effect is not considered in o-Fluoro phenol.