Chapter 10, Problem 10.19P

(a)

Interpretation Introduction

Interpretation:

The given mixed after that the $\text{pH}$ value change or not has to be explained.

Concept introduction:

Henderson-Hassel Balch equation

$\begin{array}{l}\text{pH}\text{=}{\text{pK}}_{\text{1}}\text{+log}\frac{\left[{\text{HA}}^{\text{-}}\right]}{\left[{\text{H}}_{\text{2}}\text{A}\right]}\\ \text{pH}\text{=}{\text{pK}}_{\text{2}}\text{+log}\frac{\left[{\text{A}}^{\text{2-}}\right]}{\left[{\text{HA}}^{\text{-}}\right]}\end{array}$

The $\text{pH}$ of solution can be calculated as,

$\text{pH=}\text{-log}{\left[{\text{H}}^{\text{+}}\right]}_{\text{γ}}{}_{{\text{H}}^{\text{-}}}$

With the above equation, the negative logarithm of activity of Hydrogen ion can be measured.

(b)

Interpretation Introduction

Interpretation:

The weight of selected compound ${\text{Na}}_{\text{2}}\text{HPO}\text{and}{\text{NaH}}_{\text{2}}{\text{PO}}_{\text{4}}$ has to be calculated.

Concept introduction:

Henderson-Hassel Balch equation

$\begin{array}{l}\text{pH}\text{=}{\text{pK}}_{\text{1}}\text{+log}\frac{\left[{\text{HA}}^{\text{-}}\right]}{\left[{\text{H}}_{\text{2}}\text{A}\right]}\\ \text{pH}\text{=}{\text{pK}}_{\text{2}}\text{+log}\frac{\left[{\text{A}}^{\text{2-}}\right]}{\left[{\text{HA}}^{\text{-}}\right]}\end{array}$

The $\text{pH}$ of solution can be calculated as,

$\text{pH=}\text{-log}{\left[{\text{H}}^{\text{+}}\right]}_{\text{γ}}{}_{{\text{H}}^{\text{-}}}$

With the above equation, the negative logarithm of activity of Hydrogen ion can be measured.

(c)

Interpretation Introduction

Interpretation:

To prepare buffer solution exactly $\text{pH}\text{=}7.45$ has to be explained.