chemistry

What is the concentration of the unknown H3PO4 solution? The neutralization reaction is H3PO4(aq)+3NaOH(aq)→3H2O(l)+Na3PO4(aq). A 32.00 mL sample of an unknown H3PO4 solution is titrated with a 0.100 M NaOH solution. The equivalence point is reached when 26.28 mL of NaOH solution is added.