15. Solving a chemistry problem

6. A sample of 0.2315 g of a sample of technical ammonium hydrogen phosphate was processed in a device for distillation of 50 ml of 40% NaOH solution during boiling. The released ammonia was absorbed by 40 ml of 0.051 M pa-a H2SO4. After ammonia was distilled off, the H2SO4 solution, which absorbed NH3, was titrated with 11.12 ml of a 0.09M NaOH solution. Calculate the content of (NH4)2HPO4 in the sample.