Calculate The Concentration of H+ Following Solutions 0.122 M Hoh

When water dissociates, it forms equal concentrations of H+ and OH- ions. This calculator determines the concentration of H+ ions in a solution of pure water or a dilute HOH solution.

Introduction

Water (HOH) is a neutral substance that dissociates into equal concentrations of hydrogen ions (H+) and hydroxide ions (OH-). The dissociation constant (Kw) of water is a fundamental constant that describes this process. For pure water at 25°C, Kw is approximately 1.0 × 10⁻¹⁴.

In dilute solutions of water, the concentration of H+ ions can be calculated using the dissociation constant. This is particularly useful in chemistry and biology when studying aqueous solutions.

Formula

The concentration of H+ ions in a solution can be calculated using the following formula:

[H+] = √(Kw × [HOH])

Where:

[H+] = concentration of H+ ions (Molarity, M)
Kw = dissociation constant of water (1.0 × 10⁻¹⁴ at 25°C)
[HOH] = concentration of water (Molarity, M)

For pure water, [HOH] = 55.5 M (the molar concentration of water in pure water). In dilute solutions, [HOH] is approximately equal to the concentration of the solution.

Example Calculation

Let's calculate the concentration of H+ ions in a 0.122 M solution of HOH.

Given:

Kw = 1.0 × 10⁻¹⁴
[HOH] = 0.122 M

Calculation:

[H+] = √(1.0 × 10⁻¹⁴ × 0.122) = √(1.22 × 10⁻¹⁵) ≈ 1.105 × 10⁻⁷ M

This means the concentration of H+ ions in a 0.122 M solution of HOH is approximately 1.105 × 10⁻⁷ M.

Interpreting Results

The calculated concentration of H+ ions helps determine the acidity or basicity of a solution. A higher concentration of H+ ions indicates a more acidic solution, while a lower concentration indicates a more basic solution.

In the case of a 0.122 M solution of HOH, the concentration of H+ ions is very low (1.105 × 10⁻⁷ M), which means the solution is slightly acidic. This is expected because even pure water has a small concentration of H+ ions due to its dissociation.

FAQ

What is the dissociation constant of water (Kw)?

The dissociation constant of water (Kw) is a measure of how much water dissociates into H+ and OH- ions. At 25°C, Kw is approximately 1.0 × 10⁻¹⁴.

How do I calculate the concentration of H+ ions in a solution?

Use the formula [H+] = √(Kw × [HOH]), where Kw is the dissociation constant of water and [HOH] is the concentration of water in the solution.

What does a high concentration of H+ ions indicate?

A high concentration of H+ ions indicates a more acidic solution. A low concentration indicates a more basic solution.