Chapter 17, Problem 3E

Interpretation Introduction

(a)

Interpretation:

The change in the pH value is to be determined when ${\text{NaNO}}_{\text{2}}$ of 0.100 mol is added to the 0.100 M ${\text{HNO}}_{\text{2}}$ of volume 1.00 L.

Concept introduction:

The dissociation constant of the weak acid is calculated by the following formula-

$\text{HA}\rightleftharpoons {\text{H}}^{+}+{\text{A}}^{-}$

The expression can be written as follows:

$K_a=\frac{[{\text{H}}^{+}][{\text{A}}^{-}]}{[\text{HA}]}$

The value of pH will be calculated by the following equation −

$\text{pH}=-{\log }_{10}[{\text{H}}^{+}]$

The Henderson − Hasselbalch equation −

$\text{pH}=p{K}_a+\log \frac{[{\text{A}}^{-}]}{[\text{HA}]}$

Interpretation Introduction

(b)

Interpretation:

The reason the for change in the value of pH is to be determined when ${\text{NaNO}}_{\text{2}}$ of 0.100 mol is added to the 0.100M ${\text{HNO}}_{\text{3}}$ of volume 1.00L.

Concept introduction:

The dissociation constant of the weak acid is calculated by the following formula-

$\text{HA}\rightleftharpoons {\text{H}}^{+}+{\text{A}}^{-}$

The expression can be written as follows:

$K_a=\frac{[{\text{H}}^{+}][{\text{A}}^{-}]}{[\text{HA}]}$

The value of pH will be calculated by the following equation −

$\text{pH}=-{\log }_{10}[{\text{H}}^{+}]$