Question

Describe how to calculate pH from the concentration of H⁺ or OH^-.

Short answer

The pH can be calculated using pH formula.

Step-by-step solution

Introduction

The negative log 10 of the hydrogen ion concentration in an aqueous solution is defined as pH.

Concentration of H+ and OH-

The pH scale classifies values below 7 as acidic and those over 7 as basic, whereas, pH 7 is consideredneutral or physiological pH. The amount of${\mathrm{H}}^{+}$ ions in solution increases under an acidic state, lowering the pH. Similarly, an increase in the concentration of the${\mathrm{OH}}^{-}$ (hydroxyl) ion elevates the pH value over .

Example calculation of pH

$\begin{array}{l}{\mathrm{H}}_2{\mathrm{OH}}^{+}+{\mathrm{OH}}^{-}\\ \mathrm{pH}=-\log \left[{\mathrm{H}}^{+}\right]\\ \left[{\mathrm{H}}^{+}\right]={10}^{-\mathrm{pH}}\\ \mathrm{pH}+\mathrm{pOH}=14\\ \mathrm{pH}=-{\log }_{10}\left(1\times {10}^{-7}\right)\\ \mathrm{pH}=7\end{array}$

Therefore, the value of pHwith respect to the concentration of${\mathrm{H}}^{+}$ and is 7.