12. Solution to Chemistry Problem

41. A weighed sample of (NH4)2SO4 was dissolved in a 100.0 ml measuring flask. 50.00 ml of 0.1122 M NaOH was added to 20.00 ml of the solution and heated until NH3 was completely removed. The remaining alkali was titrated with 18.00 ml of HCl solution (20.00 ml of NaOH solution are equivalent to 21.00 ml of HCl solution). What mass of (NH4)2SO3 was contained in the initial solution?