What is the pH of a buffer solution that consists of 0.25 M HClO₂ and 0.75 M KClO₂?
K _a(HClO₂) = 1.1×10^{- 2}

Question

What is the pH of a buffer solution that consists of 0.25 M HClO₂ and 0.75 M KClO₂? K _a(HClO₂) = 1.1×10^{- 2}

Quizplus · Accepted Answer

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

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

where pKa is the acid dissociation constant of the weak acid, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid.

In this case, the weak acid is HClO and its pKa can be calculated from the given Ka value:

Ka = 1.1×10^-2
pKa = -log(Ka) = 1.96

Therefore, the Henderson-Hasselbalch equation becomes:

pH = 1.96 + log([ClO-]/[HClO])

We know that the concentration of HClO is 0.25 M and the concentration of KClO is 0.75 M, so we can calculate the concentration of ClO-:

[ClO-] = KClO = 0.75 M

Now we can substitute these values into the Henderson-Hasselbalch equation and solve for pH:

pH = 1.96 + log(0.75/0.25) = 2.44

Therefore, the pH of the buffer solution is 2.44.

What Is the PH of a Buffer Solution That Consists