# 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.

## marked as duplicate by Loong♦, ringo, orthocresol♦, Jon Custer, JanSep 23 '16 at 16:50

• $$\mathbf{NO!}$$ 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
• 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