56. Solving a chemistry problem

19. When the mixture of metal iron with iron oxide (II) weighing 12.8 g is dissolved in hydrochloric acid, hydrochloric acid is spent with a volume of 66.36 ml with a mass fraction of NSL 20 % (ρ = 1.100 g/cm3). For complete oxidation of iron oxide (II) requires all the oxygen, which is released during the decomposition of a bertell salt weighing 2.042 g. Determine the mass fraction of iron and iron oxide in the mixture.