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I was reading about $\mathrm{p}K_\mathrm{a}$ values of 2-fluorobenzoic acid and 4-fluorobenzoic acid and found that the latter had a higher value which was surprising to me. I think that intramolecular hydrogen bonding should dominate all the other effects in 2-fluorobenzoic acid as mentioned in the following figure and thus it should have a higher value:

2-fluorobenzoic acid

What is wrong with my logic?

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    $\begingroup$ See ortho effect in benzoic acid. $\endgroup$ – Light Yagami Apr 1 at 9:29
  • $\begingroup$ @Light Yagami Thanks I had forgotten about that but honestly I put this question because I have more of a doubt on why the above mentioned bonding doesn’t create any issue with the acidity of the compound. $\endgroup$ – Rishi Apr 1 at 9:32
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    $\begingroup$ @LightYagami I don't think ortho effect has a role to play here. Fluorine has too small an A Value of 0.15 compared to the groups which prominently show ortho effect, and the crystal structure here shows the cooh group almost in the plane of the ring. $\endgroup$ – Ashish Ahuja Apr 1 at 11:15

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