Calculate the pH of a 0.0255 M solution of ammonium bromide (NH4Br). The Kb of ammonia is 1.76 x 10-5

5.42

Explanation:

Step 1: Consider the dissociation of NH₄Br

NH₄Br(aq) ⇒ NH₄⁺(aq) + Br⁻(aq)

Br⁻ is the conjugate base of HBr, a strong acid, so it doesn´t react with water. NH₄⁺ is the conjugate acid of NH₃, so it does react with water.

Step 2: Consider the acid reaction of NH₄⁺

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

Step 3: calculate the acid dissociation constant for NH₄⁺

We will use the following expression.

Step 4: Calculate the concentration of H₃O⁺

We will use the following expression.

Step 5: Calculate the pH

We will use the following expression.