See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

The isoelectric point (pHi) is the pH at which the amino acid exists only as a dipolar ion with net charge zero. At isoelectric point, for a neutral amino acid,   1 2 a a i pK pK pH 2   The dissociation of cationic form of valine can be represented as C H O2C HC NH3 (CH3)2 H OH H     C H CO2 - HC NH3 (CH3)2 OH H     C H CO2 - HC NH2 (CH3)2 2 a (pK ) 1 a (pK ) Netcharge (+1) (0) (-1) The species with zero net charge exists between species with (+1) and (–1) net charges.   1 2 a a i pK pK