We’re being asked to calculate the pH of an NH3/NH4Cl buffer solution after the addition of HCl solution. The buffer solution is made up of 0.25 M NH4Cl and 0.25 M NH3.
NH4Cl dissociates completely into: NH4+ + Cl-
Since the solution is a buffer, we know that NH4+ is a weak acid and NH3 is the conjugate base. HCl will react with the base NH3.
HCl will release hydronium ions (H3O+) ins solution.
Reaction: NH3(aq) + HCl(aq) → NH4+(aq) + Cl-(aq) + H2O(l)
Calculate the pH of a solution prepared by adding 20.0 mL of 0.100 M HCl to 80.0 mL of a buffer that is comprised of 0.25 M NH3 and 0.25 M NH4Cl. Kb of NH3 = 1.8 x 10-5.
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Weak Base Strong Acid Titrations concept. You can view video lessons to learn Weak Base Strong Acid Titrations. Or if you need more Weak Base Strong Acid Titrations practice, you can also practice Weak Base Strong Acid Titrations practice problems.
What is the difficulty of this problem?
Our tutors rated the difficulty ofCalculate the pH of a solution prepared by adding 20.0 mL of...as high difficulty.