Ammonium chloride (NH₄Cl) is the salt of a weak base (ammonia, NH₃) and a strong acid (hydrochloric acid, HCl). Therefore, its solution will be acidic.

Here's why:

* Hydrolysis: When ammonium chloride dissolves in water, the ammonium ion (NH₄⁺) undergoes hydrolysis, reacting with water molecules to form hydronium ions (H₃O⁺) and ammonia (NH₃):

NH₄⁺(aq) + H₂O(l) ⇌ H₃O⁺(aq) + NH₃(aq)

* Equilibrium Shift: Since ammonia is a weak base, it does not completely ionize in water. This means the equilibrium lies to the left, favoring the formation of hydronium ions.

* pH: The presence of excess hydronium ions makes the solution acidic. The exact pH will depend on the concentration of ammonium chloride.

To calculate the pH, you would need:

1. The concentration of the ammonium chloride solution.

2. The Ka value of the ammonium ion (NH₄⁺). This is a measure of the strength of the ammonium ion as an acid.

A general rule is that solutions of salts formed from a weak base and a strong acid will have a pH less than 7, indicating an acidic solution.