Propanoic acid is treated successively with (i) Br2 / red P, then H2O; (ii) excess NH3; (iii) NaNO2 / dilute HCl at 273 K. The final organic product…

(i) Hell-Volhard-Zelinsky bromination replaces an $\alpha$-hydrogen: $\mathrm{CH_3CHBrCOOH}$. (ii) Nucleophilic substitution by excess $\mathrm{NH_3}$ gives 2-aminopropanoic acid (alanine). (iii) The primary amino group on the aliphatic $\alpha$-carbon reacts with nitrous acid to give a diazonium salt that is displaced by water, forming 2-hydroxypropanoic (lactic) acid with loss of $\mathrm{N_2}$. The $\alpha$-carbon is a stereocentre, but the HVZ step is not stereoselective and the later steps do not create a single enantiomer from an achiral precursor, so the product is racemic and optically inactive.