Chapter 13, Problem 95QAP

Interpretation Introduction

Interpretation:

Whether the saline water is acidic, basic or neutral at $80{}^{\circ }\text{C}$ needs to be determined.

Concept introduction:

The dissociation reaction of a weak acid is represented as follows:

$\text{HB}\rightleftarrows {\text{H}}^{+}+{\text{B}}^{-}$

The expression for the acid dissociation constant will be as follows:

$K_a=\frac{\left[{\text{H}}^{+}\right]\left[{\text{B}}^{-}\right]}{\left[\text{HB}\right]}$

Here, $\left[{\text{H}}^{+}\right]$ is equilibrium concentration of hydrogen ion, $\left[{\text{B}}^{-}\right]$ is equilibrium concentration of conjugate base and $\left[\text{HB}\right]$ is the equilibrium concentration of weak acid.

The pH of the solution can be calculated as follows:

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

Here, $\left[{\text{H}}^{+}\right]$ is concentration of hydrogen ion in the solution.