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>Identify the more acidic compound (and the answer is the III is more acidic than II ).

My theory as to why it must be true is, let's consider II compound, we have oxygen attached to the carbon forming a sigma and a _pi_ bond, and that oxygen has 2 filled **p** orbitals. 
Now the oxygen ortho to it (in the same II), also has 2 filled **p** orbitals. So my theory is that as we have **filled p** orbitals, they can form a _pi_ bond type interaction ( I am not calling it _pi_ bond because I am not exactly sure). So after forming the 2 _pi_ bonds, the compound is stable. Now discussing III, it also has the same theory as the above, but it is just that the _pi_ overlap is at a large distance and I think _pi_ overlap over more distance is less stable considered to a small distance. Considering this theory to be true, we can say that III is less stable (and hence more acidic) than II as the _pi_ overlap of the **p** orbitals of the two oxygen atoms are farther and long in III, and II is more stable (less acidic) as the _pi_ overlap is over a small distance. Is my theory correct? Any help is appreciated. Thank you.


  [1]: https://i.sstatic.net/uWmSi.png