If a buffer solution is 0.260 M in a weak acid (Ka=8.3×10−5) and 0.480 M in its conjugate base, what is the pH?

pH = 4.3

Explanation: The pH of a buffer solution and its conjugate base can be determine by the Henderson-Hasselbach Equation. It can be estimated because equilibrium between weak acid and its conjugate base allows the solution to not change pH when small amounts of strong acid or base are added.

pH is calculated by:

pKa is the acidic dissociation constant and it shows how much strong an acid can be. It is determined as:

For the buffer solution:

Calculating pH:

pH = 4.3

For this buffer solution and its conjugate, pH = 4.3