I wanted to know how inhibition of +M effect in o-toluic acid makes it a stronger acid than benzoic acid? OR how resonance inhition makes it more acidic? kindly explain the phenomena in detail.....thanks a lot in advance!!

o-toluic acid is stronger than benzoic acid due to ortho effect.

Explanation:

In o-toluic acid because of the presence of -CH₃ at the ortho position the -COOH group will rotate from the plane of the benzene due to which the resonance of lone pair of oxygen will not take part in the benzene group . Therefore the acidity of orthobenzoic acid (or o-toluic acid) increases significantly and this happens due to stearic crowding and is known as SIR (stearic inhibition of resonance) effect.