Chapter 16, Problem 28QP

Interpretation Introduction

Interpretation:

The concentration of hydronium ions in $\text{mol/L}$ for each given solution is to be calculated.

Concept introduction:

pH is the measure of acidity of a solution that depends on the concentration of hydronium ions and the temperature of the solution.

The formula to calculate the concentration of hydronium ions from pH is:

$\left[{\text{H}}_{\text{3}}{\text{O}}^{\text{+}}\right]={10}^{-\text{pH}}$ …… (1)

The relationship between $\left[{\text{H}}_3{\text{O}}^{+}\right]$ and $\left[{\text{OH}}^{-}\right]$ is:

$K_{\text{w}}=\left[{\text{H}}_3{\text{O}}^{+}\right]\left[{\text{OH}}^{-}\right]=1.0\times {10}^{-14}$

Rearrange the above equation for hydronium ion concentration as,

$\left[{\text{H}}_3{\text{O}}^{+}\right]=\frac{1.0\times {10}^{-14}}{\left[{\text{OH}}^{-}\right]}$ …… (2)

Molarity $\left(M\right)$ can also be written in terms of $\text{mol/L}$.