Final answer:
To find the concentration of the H₃PO₄ solution, calculate the moles of NaOH used at the equivalence point, use the stoichiometry of the reaction to find the moles of H₃PO₄, and then divide by the volume of the H₃PO₄ solution. The concentration is found to be 0.03813 M.
Step-by-step explanation:
To determine the concentration of the unknown H₃PO₄ solution, we can use the data from the titration with a known concentration of NaOH solution.
Since the neutralization reaction H₃PO₄(aq) + 3NaOH(aq) → 3H₂O(l) + Na₃PO₄(aq) involves three moles of NaOH for every mole of H₃PO₄, we can calculate the moles of NaOH used at the equivalence point and then determine the moles of H₃PO₄.
First, we calculate the number of moles of NaOH: (0.02808 L NaOH) × (0.110 M NaOH) = 0.0030888 moles of NaOH.
Since it takes 3 moles of NaOH to neutralize 1 mole of H₃PO₄, the moles of H₃PO₄ will be a third of the moles of NaOH: 0.0030888 moles NaOH ÷ 3 = 0.0010296 moles H₃PO₄.
Finally, to find the concentration of H₃PO₄, we divide the moles of H₃PO₄ by the volume of the H₃PO₄ solution in liters:
Concentration of H₃PO₄= 0.0010296 moles ÷ 0.02700 L
= 0.03813 M.
Therefore, the concentration of the unknown H₃PO₄ solution is 0.03813 M.