A buffer solution is composed of 1.00 mol of acid and 3.25 mol of the conjugate base. If the pKa of the acid is 5.00, what is the pH of the buffer?

Answer 1

To calculate the pH of the buffer solution, we will use the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

Where pKa is the logarithmic form of the acid dissociation constant (Ka), [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid.

Given:
pKa = 5.00
[A-] = 3.25 mol
[HA] = 1.00 mol

Plugging in these values into the Henderson-Hasselbalch equation:

pH = 5.00 + log(3.25/1.00)

Calculating this equation:

pH = 5.00 + log(3.25) - log(1.00)
= 5.00 + 0.511 - 0.000
= 5.51

Therefore, the pH of the buffer solution is 5.51.