Calculate the mass fraction in an aqueous solution of lithium nitrite, 200 ml volume (solution density 1,119 g/ml), if titration of 15 ml aliquots of a solution of this substance consumes 16,21 ml of titrant potassium permanganate (c1/zT) = 0,099 mol/l. Write: a) reaction scheme; b) factors of equivalence of participants of reaction; c) the expression of the law of equivalents for this reaction; d) type of chemical reaction (titration method); e) indicator for determination of equivalence point (choice to explac)