Interactions of iron hydroxide 3 with hydrochloric acid make up the reaction.

The reaction equation will be:

Fe (OH) 3 + HCl = FeCl3 + HOH, where Fe (OH) 3 is iron (3) hydroxide, HCl is hydrochloric acid, FeCl3 is ferric chloride (3), HOH is water (usually they write H2O, but to make it clearer with further calculations, we will write it in this form).

Now we need to equalize the reaction equation. To do this, we need the amount of each substance to coincide on the left and right sides of the equation. That is, if we have three OH groups on the left side (respectively, 3 hydrogen and 3 oxygen, if we take the elements separately), then there should be 3 OH groups on the right side of the equation. By analogy, we arrange the coefficients where necessary and we get:

Fe (OH) 3 + 3HCl = FeCl3 + 3HOH.