# Calculate pH from OH.

#### Understand the Problem

The question is asking how to calculate the pH from the concentration of hydroxide ions (OH-). This involves using the relationship between pH and pOH, where pH = 14 - pOH. To find pH, we first need to determine pOH from the hydroxide ion concentration and then subtract that value from 14.

The pH can be calculated as $\text{pH} = 14 + \log [\text{OH}^-]$.

The final answer for pH, given the concentration of hydroxide ions, can be calculated using the steps provided.

#### Steps to Solve

1. Calculate the pOH from [OH⁻]

To find pOH, we use the formula: $$\text{pOH} = -\log [\text{OH}^-]$$ where $[\text{OH}^-]$ is the concentration of hydroxide ions.

1. Calculate the pH from pOH

Once we have pOH, we can find pH using the relationship: $$\text{pH} = 14 - \text{pOH}$$ This gives us the final pH of the solution.

1. Example of the calculations

If, for example, the concentration of hydroxide ions is $0.01 , \text{M}$, we would first calculate: $$\text{pOH} = -\log(0.01) = 2$$ Then calculate pH: $$\text{pH} = 14 - 2 = 12$$

The final answer for pH, given the concentration of hydroxide ions, can be calculated using the steps provided.

• Confusing the relationship between pH and pOH; remember, $\text{pH} + \text{pOH} = 14$.