How does the position of an electron donating group affect acidity in benzoic acid?
The strength of the acid is determined by strength of the positive charge that is on the carbonyl carbon so in case of the presence of an electron donating group you have also to check what is its inductive effect whether it has an electronegative part which would attract electrons towards it or not ....the best way is to draw the resonating structure for every case and you will reach how is the activity affected by the EDG in different positions..one last factor you have to bear in mind is that the presence of an OH group in ortho position to the COOH will form a hydrogen bond which makes it even more stable than other positions ..if we take salicylic acid as an example then the strength is ortho>meta>para