Answer:
A reaction between a strong acid and a weak base.
Explanation:
The conjugate acid of a weak base is a strong acid.
[tex]\underbrace{\hbox{H}_{3}\text{O}^{+}}_{\hbox{acid}} + \underbrace{\hbox{B}}_{\hbox{base}} =\underbrace{\hbox{BH}^{+}}_{\hbox{acid}} + \underbrace{\hbox{H}_{2}\text{O}}_{\hbox{acid}}[/tex]
The reaction above is reversible, so we can write
[tex]\underbrace{\hbox{BH}^{+}}_{\hbox{acid}} + \underbrace{\hbox{H}_{2}\text{O}}_{\hbox{base}}\rightleftharpoons \underbrace{\hbox{H}_{3}\text{O}^{+}}_{\hbox{acid}} + \underbrace{\hbox{B}}_{\hbox{base}}[/tex]
Thus, the solution of the salt will be acidic, because it produces hydronium ions.
Example;
Ammonium chloride is the salt of a strong acid (HCl) and a weak base (NH₃).
Solutions of NH₄Cl are acidic.
