This is an acid-base reaction (neutralization): HF is an acid, Ba(OH)2 is a base.

This is a precipitation reaction: BaF2 is the formed precipitate.

### Word equation

hydrogen fluoride + barium hydroxide → water + barium fluoride

### Input interpretation

HF + Ba(OH)2 → H2O + BaF2

Hydrogen fluoride barium hydroxide water barium fluoride

### Balanced equation

Balance the chemical equation algebraically:

HF + Ba(OH)2 → H2O + BaF2

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

c1HF + c2Ba(OH)2 → c3H2O + c4BaF2

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

F: c1 = 2c4

H: c1+ 2c2 = 2c3

Ba: c2 = c4

0: 2c2 = c3

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 c2 = 1 and solve the system of equations for the remaining coefficients:

c1 = 2 c2=1

c3=2 c4=1

Substitute the coefficients into the chemical reaction to obtain the balanced

equation: