To calculate the concentration of hydroxide ions (OH-) from the pH of a solution, you can use the equation:
OH- concentration = 10^-(pH)
Here's a step-by-step explanation of how to calculate OH- concentration from pH:
Determine the pH of the solution. The pH value represents the negative logarithm (base 10) of the hydrogen ion concentration (H+).
Take the negative value of the pH. For example, if the pH is 4, the negative value would be -4.
Calculate 10 raised to the power of the negative pH value. This can be done using a scientific calculator or by using the exponentiation function on a calculator. For example, if the pH is 4, you would calculate 10^(-4).
The result will give you the concentration of hydrogen ions (H+) in the solution. Since water dissociates into equal concentrations of H+ and OH- ions in pure water, this value will also represent the concentration of hydroxide ions (OH-) in the solution.
It's important to note that this calculation assumes that the solution is aqueous and at 25 degrees Celsius. In more complex scenarios or in the presence of other species that can influence the pH, additional calculations or considerations may be necessary.