55. Solving a chemistry problem

4. Calculate the mass fraction of sodium hydroxide and hydroxylamine in the solution, if when titrating 10.0 ml of solution (ρ = 1.0 g/ml) the volume of 0.1 M HCl (K = 0.9570) at the first equivalence point was 5.7 ml, and in the second - 10.3 ml.