# Reference Guides

### Introduction

“pH” is an abbreviation for “potential of hydrogen”. It is a unit of measurement that stands for the concentration of hydrogen ions that are within a solution. When an acid or base is mixed with water, the compound disassociates into ions. In acids one of the ions is a hydrogen ion (H+), In acids, one of the ions is a hydroxide ion (OH-). The concentration of ions is commonly described by the pH scale as a numeric value.

In this guide, we will be going over a few different ways to find pH, pOH, acid concentration, and base concentration[OH].

### Guide

• Given [H+] = 4.1 x 10-4M, find the following: We have the concentration and will attempt to find:
• pH
• pOH
• [OH]

To find the pH we will use the following formula using the given acid concentration: pH = – log (4.1 x 10-4M)

Note: The number of sig figs will be the number of decimal places pH and pOH should be rounded to

As we have found the pH we can now use the following formula to find the pOH: 3.39 + pOH = 14

After subtracting 3.39 from both the pH and 14 we will get the pOH.

Answer: (3.39 – 3.39)+(14 – 3.39)= pOH 10.61

As we have found the pOH, we will now go ahead with finding the base concentration [OH]. To do this can use the following formula: [OH] = 10-10.61

Answer: [OH] = 2.5 x 10-11M

### Conclusion

Hydrogen Ions are present in all aqueous solutions. The concentration of these ions in a solution is important in determining the properties of a solution and the chemical behaviors of its other solutes.

A solution is considered neutral if it has equal concentrations of hydronium and hydroxide ions and acidic if it has more hydronium ions than hydroxide ions; and basic if it contains a lesser concentration of hydronium ions than hydroxide ions.