Chapter 17, Problem 105SAE

Interpretation Introduction

Interpretation:

The pH of the buffer solution formed by mixing 1.49 M $\left[{\text{C}}_{\text{2}}{\text{H}}_{\text{5}}{\text{NH}}_{\text{2}}\right]$ and 1.001 $\left[{\text{HClO}}_{\text{4}}\right]$

needs to be calculated, if the value of $K_b=4.3\times {10}^{-4}$ needs to be determined.

Concept introduction:

For a buffer solution, the pH can be determined using the following relation.

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

Here, $p{K}_a$ is calculated as follows:

$p{K}_a=-\log K_a$

Where, $K_a$ is acid dissociation constant of weak acid.

The relation between acid dissociation constant and base dissociation constant is as follows:

$K_w=K_a\times K_b$

Here, $K_w$ is ionic product of water.