What is the chemical equation that describes the complete neutralization of H3PO4 by NaOH?

A. H3PO4 + 2NaOH Na2HPO4 + 2H2O
B. H3PO4 + H2O H2PO4- + H3O+
C. H3PO4 + NaOH NaH2PO4 + H2O
D. H3PO4 + 3NaOH Na3PO4 + 3H2O

You should learn how to write arrows. Answer is D.

D. H3PO4 + 3NaOH -><- Na3PO4 + 3H2O

The chemical equation that describes the complete neutralization of H3PO4 by NaOH is:

C. H3PO4 + NaOH NaH2PO4 + H2O

To determine the correct chemical equation for the complete neutralization of H3PO4 by NaOH, we need to understand the concept of neutralization reactions and the rules for balancing chemical equations.

In a neutralization reaction, an acid and a base react to form a salt and water. The general form of a neutralization reaction is:

Acid + Base Salt + Water

In this case, H3PO4 (phosphoric acid) is the acid and NaOH (sodium hydroxide) is the base. The salt formed will contain the cation (positive ion) from the base and the anion (negative ion) from the acid.

To balance the chemical equation, we need to ensure that the same number of atoms of each element are present on both sides of the equation.

Now, let's evaluate the options given:

A. H3PO4 + 2NaOH Na2HPO4 + 2H2O
This option balances the equation with 2 moles of NaOH, forming Na2HPO4 (sodium dihydrogen phosphate) as the salt. This equation is correct.

B. H3PO4 + H2O H2PO4- + H3O+
This equation does not involve NaOH and represents the ionization of H3PO4 into H2PO4- (dihydrogen phosphate) and H3O+ (hydronium ion). It does not describe a neutralization reaction and is not the correct answer.

C. H3PO4 + NaOH NaH2PO4 + H2O
This option balances the equation with 1 mole of NaOH, forming NaH2PO4 (sodium dihydrogen phosphate) as the salt. This equation is correct.

D. H3PO4 + 3NaOH Na3PO4 + 3H2O
This option balances the equation with 3 moles of NaOH, forming Na3PO4 (sodium phosphate) as the salt. This equation is incorrect.

Therefore, the correct chemical equation that describes the complete neutralization of H3PO4 by NaOH is option A: H3PO4 + 2NaOH Na2HPO4 + 2H2O.