2. Solving a chemistry problem

174. A weighed portion of anestezin (H2N-C6H6-COO-C2H5; М.m. = 165.19) weighing 1.5964 g was dissolved in a volumetric flask with a capacity of 100.00 cm3. For titration of 15.00 cm3 of the resulting solution after acidifying it with hydrochloric acid, 13.82 cm3 of a 0.1 M sodium nitrite solution with K = 1.002 was used. Calculate the mass fraction of anesthesin in the sample.