Neutralization takes place when an acid and a base reacts to form water and a salt. The substances that are involve in this reaction are H3O+ ion, OH- ion, acid and a base. A neutral compound cannot participate in the neutralization process. Example of this reaction is HCl + NaOH -> NaCl + H2O. The HCl contains an H3O+ ion. The NaOH contains the OH- ion and NaCl is a salt. The NaCl salt is the product of the neutralization process.