44. Solving a chemistry problem

301. A portion of sodium carbonate weighing 0.2458 g was dissolved and 20.00 cm3 of a 0.04500 M solution of magnesium sulfate was added to the solution. The excess of the latter was titrated with 15.00 cm3 of complexone III solution (1 cm3 of magnesium sulfate is equivalent to 1.25 cm3 of complexone III). Write the reaction equation. Describe the scheme of analysis, pH of the solution, indicate the buffer solutions.