Calculate H+ Ph Poh Nd Oh for 2.0 M Naoh

Introduction

When NaOH dissolves in water, it completely dissociates into Na+ and OH- ions. The concentration of OH- ions is equal to the molarity of the NaOH solution. This strong base solution has a high pH, typically above 12 for concentrated solutions.

The pH of a solution is a measure of its acidity or basicity. It's calculated using the formula:

For a strong base like NaOH, the concentration of H+ ions is very low, resulting in a high pH value.

Formula

The key relationships for a NaOH solution are:

Where Kw is the ion product of water (1.0 × 10⁻¹⁴ at 25°C).

Example Calculation

For a 2.0 M NaOH solution:

1. Determine [OH-]: [OH-] = [NaOH] = 2.0 M
2. Calculate [H+]: [H+] = Kw / [OH-] = 1.0 × 10⁻¹⁴ / 2.0 = 5.0 × 10⁻¹⁵ M
3. Find pH: pH = -log(5.0 × 10⁻¹⁵) ≈ 14.3
4. Calculate POH: POH = 14 - pH ≈ 0.3

The result shows this is a very basic solution with a pH of approximately 14.3.

Interpreting Results

A pH of 14.3 indicates a highly basic solution. The [H+] is extremely low (5.0 × 10⁻¹⁵ M), while [OH-] is high (2.0 M). The POH value of 0.3 confirms the basic nature of the solution.