Chapter 2, Problem 10P

Summary Introduction

To determine: The compound that has lowest $\text{pH}$ out of ( $\text{0}\text{.1 M}$ $\text{HCl}$), ( $\text{0}\text{.1 M}$ acetic acid; ${\text{pK}}_{\text{a}}$ is $4.86$), and ( $\text{0}\text{.1 M}$ formic acid; ${\text{pK}}_{\text{a}}$ is $3.75$).

Introduction:

The two ionic species hydrogen ion and hydroxide ion are formed by the splitting of water. The hydrogen ions and hydroxide ions are released in equal number when the water is dissociated. The alkalinity or acidity of the solution is determined by the $\text{pH}$ (potential of hydrogen) of a solution. The $\text{pH}$ of a solution is defined as the negative logarithm of the molar ion hydrogen ( ${\text{H}}^{\text{+}}$) ion concentration. It is calculated by the formula $\text{pH}=-{\text{log [H}}^{+}\text{]}$.