Chapter 8, Problem 85P

Interpretation Introduction

Interpretation:

The $\frac{{\text{H}}_{\text{3}}{\text{BO}}_{\text{3}}}{{\text{H}}_{\text{2}}{\text{BO}}_{\text{3}}{}^{-}}$ ratio in a borate buffer solution that has a pH of 8.40 should be calculated.

Concept Introduction:

The pH of buffer solution is calculated using the following formula:

$\text{pH }={\text{ pK}}_{\text{a}}+\text{ log}\frac{\left[{\text{A}}^{-}\right]}{\left[\text{HA}\right]}$

This is known as Henderson- Hasselbalch equation. Here, $p{K}_{\text{a}}$ is negative log of acid dissociation constant, $\left[{\text{A}}^{-}\right]$ is concentration of conjugate base and $\left[\text{HA}\right]$ is concentration of acid.