# How many moles of sodium hydroxide are needed to neutralize 1 mole of phosphoric acid?

May 19, 2014

You need 3 mol of sodium hydroxide to neutralize 1 mol of phosphoric acid.

#### Explanation:

The balanced equation for the reaction is

$\text{3NaOH" + "H"_3"PO"_4 → "Na"_3"PO"_4 + 3"H"_2"O}$

Phosphoric acid ${\text{H"_3"PO}}_{4}$ is a triprotic acid. It has three acidic hydrogen atoms.

Thus, one molecule of phosphoric acid will need three formula units of sodium hydroxide, and

One mole of phosphoric acid will need three moles of sodium hydroxide.

This is what the balanced equation tells us:

3 mol of $\text{NaOH}$ reacts with 1 mol of ${\text{H"_3"PO}}_{4}$.