Final answer:
Water and a salt are always produced in an acid-base neutralization reaction.
Step-by-step explanation:
The substances that are always produced in an acid-base neutralization reaction are water and a salt. When an acid and a base react, they cancel each other's chemistry and form water and a salt. For example, the neutralization reaction between sodium hydroxide and hydrochloric acid produces sodium chloride (a salt) and water:
NaOH + HCl → NaCl + H2O