What is the pH of a buffer solution where [HA] = [A^-]?

Question

Quizplus · Accepted Answer

The pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]). However, in this case, the concentration of A- cannot be determined from the given information. Instead, the given concentrations can be used to calculate the ratio of [A-]/[HA]. Since the buffer is composed of HA and its conjugate base, the ratio is equal to Ks1u1B1as1u1B0, the acid dissociation constant (Ka) for HA. Taking the negative log of this value gives the pKa, which can be added to the log of the ratio to obtain the pH of the buffer solution. Therefore, the correct answer is C.

What Is the PH of a Buffer Solution Where [HA]