The absorption spectrum NO3 in aq. soln. and the kinetics of the reactions with Cl- and OH- were detd. by using laser-spectrometric techniques. The max. absorption was at 635 nm with a decadic absorption coeff. of e = (530 +- 110) L/mol.cm. At 298 K rate consts. of k1 = (1.0 +- 0.2).107 L/mol.s for the reaction with Cl- and of k2 = (8.2 +- 0.9).107 L/mol.s for the reaction with OH- were obtained.