# Question fe332

May 1, 2016

#### Explanation:

As you know, a solution's pH is simply a measure of its concentration of hydronium ions, ${\text{H"_3"O}}^{+}$, which you'll often times see referred to as hydrogen ions, ${\text{H}}^{+}$.

More specifically, the pH of a solution is calculated by taking the negative log base 10 of the concentration of hydrogen ions.

color(blue)(|bar(ul(color(white)(a/a)"pH" = - log(["H"^(+)])color(white)(a/a)|)))

This means that all you have to do to determine the pH of a solution of known concentration of hydrogen ions is to use that equation. In your case, you know that

["H"^(+)] = "0.020 M"#

The pH of the solution will thus be

$\text{pH} = - \log \left(0.020\right) = 1.699 \approx \textcolor{g r e e n}{| \overline{\underline{\textcolor{w h i t e}{\frac{a}{a}} 1.70 \textcolor{w h i t e}{\frac{a}{a}} |}}}$