Chapter 19, Problem 19.106P

Interpretation Introduction

Interpretation:

The volumes of an equimolar aqueous solution of ${\text{KH}}_{\text{2}}{\text{PO}}_{\text{4}}$ and ${\text{K}}_{\text{2}}{\text{HPO}}_{\text{4}}$ that must be combined to make $100\text{ mL}$ of $\text{pH}$ of $7$ buffer are to be calculated.

Concept introduction:

The strong acids have lower $\text{pH}$ value but they have a higher concentration of $\left[{\text{H}}_3{\text{O}}^{+}\right]$.

The buffer solution is the type of solution that consists of a weak acid and its conjugate base.

The expression to calculate the concentration of solute is as follows:

$\text{Concentration of solute}=\frac{\left(\text{Moles of solute}\right)}{\left(\text{Volume of solution}\right)}$

The expression to calculate $\text{pH}$ of the buffer solution is given as follows:

  $\text{pH}={\text{pK}}_{\text{a2}}+\log \left[\frac{\text{Conjugate base}}{\text{Acid}}\right]$        (1)

Here, $K_{\text{a2}}$ is the second acid dissociation constant.

The expression to calculate the acid dissociation constant is as follows:

  $\text{p}{K}_{\text{a2}}=-\log \left(K_{\text{a2}}\right)$        (2)

Here, $K_{\text{a2}}$ is the second acid dissociation constant.