What is the net ionic equation for the reaction between phosporic acid and sodium hydroxide?

Answer 1

Update 7/6/2012:

Molecular Equation:

H3PO4(aq) + 3NaOH(aq) [bidirectional arrows] Na3PO4(aq) + 3H2O(l)

Total Ionic Equation:

H3PO4 + 3Na+ + 3OH- [bidirectional arrows] 3Na+ + PO43- + 3H2O

Net Ionic Equation:

H3PO4 + 3OH- [bidirectional arrows] PO43- + 3H2O

Here, H3PO4 is a weak acid therefore it does not fully dissociate in water. Therefore, when writing the Total Ionic/Net Ionic equations, weak acids don't "split apart" and are kept together. Only strong acids and strong bases fully dissociate (100% ionization) in water. You should memorize the strong acids to help you with Acid-Base reactions (some textbooks say there are 7, others say there are 6).

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(Previous response to question below):

Molecular/Ionic Compound Equation:

H3PO4+3NaOH----->Na3PO4+3H2O

Full Ionic Equation (Charges written in parentheses):

H3PO4+3Na(+) + 3OH(-) ------------>3Na(+) +PO4 (3-) +3H2O

Net Ionic Equation:

(H+) + (H3PO4-) + (3OH-) ----------->(PO4 3-) + 3H2O

Notice that the sodium ions are eliminated to make the net ionic equation because they are present in both products and the reactants. Also notice that the charges on each side of the net ionic equation are equal, 3 hydroxide ions, each with a 1- charge on the left, and one phosphate ion with a 3- charge on the right.

Answer 2

3NaOH + H3PO4 ->Na3PO4 +3H2O

Answer 3

H3PO4 + 3NaOH >> Na3PO4 + 3H2O