23. Solution to Chemistry Problem

2. A weighed sample of (NH4)2SO4 was dissolved in a 100 ml measuring flask. 49.21 ml of 0.1531 M NaOH was added to 20 ml of the solution and heated until NH3 was completely removed. The remaining alkali was titrated with 20.76 ml of HCl solution (15.42 ml of NaOH solution are equivalent to 21.27 ml of HCl solution). What mass of (NH4)2SO4 was contained in the initial solution?