What is the pH of a 0.1 M solution of ammonium chloride (NH4Cl)? (2019) 2019
Practice Questions
Q1
What is the pH of a 0.1 M solution of ammonium chloride (NH4Cl)? (2019) 2019
5.10
4.75
6.00
7.00
Questions & Step-by-Step Solutions
What is the pH of a 0.1 M solution of ammonium chloride (NH4Cl)? (2019) 2019
Step 1: Identify the components of ammonium chloride (NH4Cl). It is made from ammonium (NH4+), which comes from a weak base (ammonia, NH3), and chloride (Cl-), which comes from a strong acid (hydrochloric acid, HCl).
Step 2: Understand that when NH4Cl dissolves in water, it dissociates into NH4+ and Cl-. The Cl- does not affect the pH because it is from a strong acid.
Step 3: Recognize that NH4+ can react with water in a process called hydrolysis, which produces H+ ions and NH3. This reaction can lower the pH of the solution.
Step 4: Use the formula for the hydrolysis of NH4+: NH4+ + H2O ⇌ NH3 + H+. This reaction shows that NH4+ produces H+ ions, making the solution acidic.
Step 5: Calculate the pH using the concentration of NH4+. For a 0.1 M solution, you can use the formula: pH = -log[H+].
Step 6: Find the concentration of H+ produced from the hydrolysis of NH4+. This can be estimated using the Kb of NH3 and the concentration of NH4+. The pH is approximately 4.75.
