Why are some salts still acidic or basic?

Salts can be acidic or basic depending on the cation and anion they are composed of. If the cation comes from a weak base or the anion comes from a weak acid, the salt can be acidic or basic. For example, ammonium chloride is acidic because the ammonium ion comes from a weak base (ammonia) while the chloride ion comes from a strong acid (hydrochloric acid).