Chapter 21, Problem 42QAP

Interpretation Introduction

Interpretation:

The volume of ${\text{Cl}}_{\text{2}}$ gas needed to remove ${\text{H}}_{\text{2}}\text{S}$ from the given volume of water and pH of the solution needs to be determined.

Concept introduction:

The reaction between ${\text{H}}_{\text{2}}\text{S}$ and ${\text{Cl}}_{\text{2}}$ leads to the formation of solid Sulphur hence it is used to remove the impurity of ${\text{H}}_{\text{2}}\text{S}$ from the contaminated water. The balanced equation between ${\text{H}}_{\text{2}}\text{S}$ and ${\text{Cl}}_{\text{2}}$ can be written as follows:

${\text{H}}_{\text{2}}\text{S}(aq)\text{ + Cl2}(aq)\to {\text{2H}}^{\text{+}}(aq){\text{ +2Cl}}^{\text{-}}(aq)\text{ +S}(s)$

The mole concept can be used to calculate the volume of ${\text{Cl}}_{\text{2}}$ that is used to remove given amount of ${\text{H}}_{\text{2}}\text{S}$ gas. Because of free ${\text{H}}^{\text{+}}$ ions in the solution, the solution becomes acidic and the pH can be calculated as follows:

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