# Hydroxide ion Concentration Calculator from pH and pOH

The Hydroxide Ion Concentration Calculator is a versatile tool designed to facilitate the calculation of the hydroxide ion concentration ([OH^{–}]) in a solution based on the given pH or pOH values.

This calculator is instrumental in understanding the basic principles of acid-base chemistry and provides insights into the alkalinity or basicity of a solution.

## Welcome to the Hydroxide Ion Concentration Calculator

## How to Use the Calculator?

**Input Selection:** Users have the flexibility to input either the pH or pOH value, choosing the appropriate selection from the dropdown menu.

**Data Entry:** Enter the pOH or pH value into the designated field.

**Calculation:** Upon clicking the “Calculate” button, the calculator swiftly processes the input and computes the corresponding [OH^{–}] concentration and displays it along with the associated pH or pOH value.

## Measuring Hydroxide Ion Concentration from pOH and pH

**Relationship between pH, pOH, and Hydroxide Ion Concentration:** The hydroxide ion concentration ([OH^{–}]) in a solution can be calculated using the given pH or pOH values. Understanding the relationship between these parameters is fundamental:

**pH and pOH Relationship**: In an aqueous solution at 25°C, the sum of pH and pOH is always 14. This relationship remains constant due to the auto-ionization of water.

pH + pOH = 14

### Calculating Hydroxide Ion Concentration [OH^{–}] from pOH

Given the pOH value, the hydroxide ion concentration can be determined using the formula:

**From pOH Equation**: If the pOH of a solution is known, the [OH^{–}] concentration can be calculated.

pOH = -log[OH^{–}]

**Example**: For a solution with a pOH of 4:

- Using the pOH equation:
- pOH = 4
- -log[OH
^{–}] = 4 - [OH
^{–}] = 1.00 × 10^{-4}M

### Calculating Hydroxide Ion Concentration [OH⁻] from pH

Similarly, [OH⁻] can be calculated when the pH is given using the relationship between pH and pOH:

**From pH Equation**: If the pH of a solution is provided, the [OH⁻] concentration can be deduced.

- pH + pOH = 14
- pOH = 14 – pH

**Example**: For a solution with a pH of 11.6:

- Using the pH + pOH equation:
- pH + pOH = 14
- 11.6 + pOH = 14
- pOH = 14 – 11.6
- pOH = 2.4

**Further Calculation**:

From the pOH equation:

- pOH = 2.4
- -log[OH⁻] = 2.4
- [OH⁻] = 2.51 × 10
^{-12}M