### Input interpretation

NaH2PO4     +    H2O    →        NaOH          +   H3PO4

Sodium          water     sodium hydroxide    phosphoric acid

dihydrogen

phosphate

phosphate

### Balanced equation

Balance the chemical equation algebraically:

NaH2PO4 + H2O → NaOH + H3PO4

Add stoichiometric coefficients, c, to the reactants and products:

c1NaH2PO4 + c2 H2O → c3 NaOH + c4 H3PO4

Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O and P:

H: 2c+2C2=C3+3C4 Na: C1=C3

O: 4C1+C2 C3 +4 C4

P: c1=C4

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:

C1 = 1 C2=1

C3 = 1 C4=1

Substitute the coefficients into the chemical reaction to obtain the balanced

equation:

NaH2PO4 + H2O → NaOH + H3PO4

Structures

Park

Na

Pa

Ho-H→ Na

O--H

Word equation

sodium dihydrogen phosphate + water →→→ sodium hydroxide + phosphoric acid