PLEASE HELP! Which is a stronger acid: 4-methoxy benzoic acid or benzoic acid and a deatailed description why?

Question

thankyou, if you could give a really in depth description why that would really help, thanks again!

Answer 1

I would expect benzoic acid to be slightly stronger. Why? Because the -OCH3 group in the para position acts as an electron-donating group to the ring which strengthens the O-H bond of the acid. A stronger O-H bond means a weaker acid since the H+ won't come off as easily. If the -OCH3 were in the meta position, it acts as an electron withdrawing group which weakens the O-H bond. Thus 3-methoxybenzoic acid is slightly stronger than benzoic acid.

Answer 2

Look up mesomeric effects in your textbook.