Take two known volumes of the solution to be tested and treat them as follows:

1. Take a known volume of the solution to be tested and add 1 to 2 drops of methyl orange indicator. Titrate the solution to be tested with a known concentration of HCl solution until the solution changes from yellow to orange, and record the volume of HCl solution used. The amount of HCl consumed is equal to 2n(Na3PO4) + n(NaOH).

2. Take another portion of the solution to be measured and add 1 to 2 drops of thymolphthalein indicator. Titrate the solution to be measured with a known concentration of HCl solution until the blue color of the solution suddenly becomes lighter, and record the volume of HCl solution used. The amount of HCl consumed is equal to n(Na3PO4) + n(NaOH). The component contents can be found from the above two sets of experimental data.

If there is time, the experiment needs to be repeated