Give reasons for the following : (i) On electrolysis in acidic solution, amino acids migrate towards cathode while in alkaline solution these migrate towards anode. (ii) The monoamino monocarboxylic acids have towp K values.

Give reasons for the following : (i) On electrolysis in acidic soluti

1.	Give reasons for the following : (i) On electrolysis in acidic solution, amino acids migrate towards cathode while in alkaline solution these migrate towards anode. (ii) The monoamino monocarboxylic acids have towp K values.
Answer» Solution :(i) Amino acids have zwitterionic structure. Therefore, in presence of strong acids they exist as cations (I) and thus on electrolysis these migrate towards cathode. `H_(3)overset(+)N-underset("Zwitterion")(CHR)-COO^(-)+H^(+)to H_(3)overset(+)(N)-underset("Cation"(I))(CHR)-COOH` In contrast , in presence of alkalies , the amino acids exist as anions (II) and thus on electrolysis , these migrate towards anode. `H_(3)overset(+)N-underset("Zwitterion")(CHR)-COO^(-)+OH^(-)to H_(2)N-underset("ANION"(II))(CHR)-COO^(-)+H_(2)O` (ii) A monoamino monocarboxylic acid such as glycine exists as a dipolar ion `(overset(+)NH_3-CH_2-COO^(-))`. In this structure , `overset(NH_3)` group acts as the acid and `COO^(-)` group acts as the base. monoamino monocarboxylic acids can act both as as acid as well as a base. THerefore , these acids have two pK VALUES one as an acid (when titrated with a base ) and other as a base (when titrated with an acid).