| Item $I$ | Item $II$ |
| $A$ Ester test | $P$ Tyr |
| $B$ Carbylamine test | $Q$ Asp |
| $C$ Phthalein dye test | $R$ Ser |
| $S$ Lys |
(a) Water solubility is maximum at a $pH$ when concentrations of anions and cations are equal
(b) They give ninhydrin test
(c) On reacting with nitrous acid give off ${N_2}$