Final answer:
The calculation of a buffer solution's pH with given concentrations of NH₃ and NH₄Cl can be done using the Henderson-Hasselbalch equation. The resulting pH is approximately 9.65.
Step-by-step explanation:
The student has asked about the calculation of the pH of a buffer solution. To calculate the pH of the buffer prepared by mixing 600 cc of 0.6 M NH₃ (ammonia) and 400 cc of 0.5 M NH₄Cl (ammonium chloride), use the Henderson-Hasselbalch equation:
pH = pKa + log ([Base]/[Acid])
NH₃ is the base and NH₄Cl provides the NH₄⁺, which is the conjugate acid. Ammonia’s pKa is 9.25. Calculate the moles of NH₃ and NH₄⁺:
- NH₃: 0.6 moles/L × 0.6 L = 0.36 mol
- NH₄Cl: 0.5 moles/L × 0.4 L = 0.20 mol
Using the Henderson-Hasselbalch equation:
pH = 9.25 + log (0.36/0.20) = 9.25 + log (1.8)
After calculating, the pH of the buffer solution is approximately 9.65, which means the solution is basic.