Final answer:
The pH of a buffer solution composed of NH4Cl and NH3 can be calculated using the Henderson-Hasselbalch equation. The specific pH cannot be determined without the pKa value of NH4+. The principles of buffer action are illustrated by the question.
Step-by-step explanation:
The question pertains to the pH calculation of a buffer solution made by mixing NH4Cl and NH3. To determine the pH, we use the Henderson-Hasselbalch equation:
pH = pKa + log(rac{[Base]}{[Acid]})
NH4Cl provides the NH4+ ion, which is the conjugate acid, and NH3 is the weak base. The pKa for NH4+ is equivalent to the -log of its Kb, which we can get from tables of thermodynamic data or calculate from the equilibrium constant of water (Kw) divided by the Kb of NH3, as NH4+ is the conjugate acid of NH3. However, without the specific value of Kb or pKa, we cannot determine the exact pH in this answer.
Assuming the pKa value is known, we could find the pH with the following steps:
- Combine the volumes of NH4Cl and NH3 solutions to determine the final concentrations of NH4+ and NH3.
- Apply the Henderson-Hasselbalch equation to find the pH.
It's important to note that to provide an exact pH value, the pKa of ammonium, proper molarity, and volume adjustments must be known. This exercise demonstrates the fundamental principles of buffer systems and how they resist changes in pH.