Final answer:
The pH of the buffer solution containing 0.216 mol/L C₅H₅N and 0.352 mol/L C₅H₅NH can be calculated using the Henderson-Hasselbalch equation with the pKa value derived from the pKb of pyridine.
Step-by-step explanation:
Calculating pH of a Buffer Solution
To determine the pH of a solution containing both C₅H₅N (pyridine) and C₅H₅NH⁺ (pyridinium ion), we need to recognize that this is a buffer system. Pyridine is a weak base and its conjugate acid is the pyridinium ion. The pKb of pyridine is 8.77, which can be used to calculate the pKa of its conjugate acid by using the relationship pKa + pKb = 14. This gives us a pKa of 5.23 for the pyridinium ion.
To calculate the pH of the buffer system we can use the Henderson-Hasselbalch equation:
pH = pKa + log([base]/[acid])
Substituting the given concentrations into the equation:
pH = 5.23 + log(0.216mol/L / 0.352mol/L)
This calculation will yield the pH of the buffer solution.