Question
A 30.0 mL sample of phosphoric acid is titrated with 18.0 mL of 3.0 M NaOH solution. What is the molarity of the phosphoric acid?
Answers
DrBob222
Phosphoric acid has three H ions; therefore, technically at least, it will have three inflections in the curve. I assume you mean for ALL of the H3PO4 to be neutralized.
3NaOH + H3PO4 ==> Na3PO4 + H2O
moles NaOH = M x L
moles H3PO4 = moles NaOH x 1/3
M H3PO4 = moles H3PO4/L H3PO4
3NaOH + H3PO4 ==> Na3PO4 + H2O
moles NaOH = M x L
moles H3PO4 = moles NaOH x 1/3
M H3PO4 = moles H3PO4/L H3PO4