I need to determine the molar concentration of phosphoric acid. A 10mL sample underwent titration analysis with sodium hydroxide. 6 trials had taken place:
Trial 1 - Used 15.1mL of NaOH, and titrated solution turned pale pink.
Trial 2 - Used 17.3mL of NaOH, and titrated solution turned pink.
Trial 3 - Used 13.3mL of NaOH, and titrated solution was clear.
Trial 4 - Used 15.3mL of NaOH, and titrated solution turned pale pink.
Trial 5 - Used 21.2mL of NaOH, and titrated solution turned dark pink.
Trial 6 - Used 14.9mL of NaOH, and titrated solution turned pale pink.
I had found the average mLs of base to neutralize the acid, this is with the pale pink results. The average base is 15.1mLs
Based on the final equation of: H3PO4 + NaOH —> Na3PO4 + H2O, I know that the ratio of moles is 1:3. Using this with the equation CV=CV, I determined the ratio of concentrations, which is 1mol/L of acid to every 4.53mol/L of base. What would be the next step to determine the concentration of acid? I cannot figure out how to do it