# Benzoic acid vs Ethanoic acid [duplicate]

A is more acidic than B. Does that mean -I effect of phenyl is greater than its +R?

Update This is the statement from my NCERT textbook.

• @Loong I am not satisfied by the answer in that question – Reeshabh Ranjan Sep 23 '16 at 14:56
• $$\mathbf{NO!}$$ There is no resonance stabilisation by the benzene ring in the benzoate ion, you can try drawing resonance forms, it does not get delocalised onto the benzene ring! – orthocresol Sep 23 '16 at 15:05
• @ZOZ Don't worry about it. It's a common mistake. I'm not angry or anything perhaps just a bit too overenthusiastic... Yes. If anything, it would be +M, although I really don't think that contributes much. As described in the text, -I is much more significant in this case. – orthocresol Sep 23 '16 at 15:18
• My two cents: There are two things at play here first, the caboxyate group is electron withdrawing, or (alternatively) the benzene ring is electron-donating within the $\pi$-electron system of the molecule, and this would have a destabilising effect. Also, the excess negative charge is not delocalised onto the bezene ring. However, benzene ring may have an electron-withdrawing effect within the $\sigma$-framework, which may be rationalised by the greater $s$ character of the $sp^2$ hybridised carbon. However, I can't say how weak/strong this effect is – getafix Sep 23 '16 at 15:19
• @AaronAbraham No I do not agree with you.NCERT textbooks are the recommended materials for all international science olympiads as an introductory course.They are wonderfully written and till date I havent found more than 1 or 2 mistakes in the 4 volumes of books.Stop defaming books.BTW the pKa value for cresol is absolutely correct in the book.See for yourself en.wikipedia.org/wiki/Cresol and see ncert.nic.in/ncerts/l/lech202.pdf – user14857 Sep 24 '16 at 10:31