Q.
Which of the following does not exist as a Zwitter ion?
Solution:
o and p-aminobenzoic acids do not exist as a Zwitter ion. The lone pair of electrons on the group is donated towards the benzene ring due to resonance effect. As a result, acidic character of -COOR group and basic character of group decrease. Therefore, the weakly acidic -COOH group cannot transfer a ion to the weakly basic group. Thus, o or p-aminobenzoic acids do not exist as Zwitter ion.
