Calculate The Ph of The Following Solutions 0.10 M Naoh

Introduction

The pH scale measures how acidic or basic a solution is, ranging from 0 (most acidic) to 14 (most basic). For strong bases like NaOH, the pH can be calculated using the concentration of the hydroxide ions ([OH⁻]) produced when the base dissolves in water.

NaOH is a strong electrolyte that dissociates completely in water according to the equation:

Since NaOH is a strong base, the concentration of hydroxide ions ([OH⁻]) is equal to the concentration of NaOH in the solution.

How to Calculate pH

The pH of a solution can be calculated using the following steps:

1. Determine the concentration of hydroxide ions ([OH⁻]) in moles per liter (M). For strong bases, [OH⁻] = [NaOH].
2. Calculate the concentration of hydrogen ions ([H⁺]) using the relationship between [H⁺] and [OH⁻] in water:
[H⁺] × [OH⁻] = 10⁻¹⁴ (at 25°C)
3. Calculate the pH using the concentration of hydrogen ions:
pH = -log₁₀[H⁺]

For a 0.10 M NaOH solution:

• [OH⁻] = 0.10 M
• [H⁺] = 10⁻¹⁴ / 0.10 = 10⁻¹³ M
• pH = -log₁₀(10⁻¹³) = 13

Example Calculation

Let's calculate the pH of a 0.10 M NaOH solution step by step:

1. Given: [NaOH] = 0.10 M
2. Since NaOH is a strong base, [OH⁻] = [NaOH] = 0.10 M
3. Calculate [H⁺]: [H⁺] = 10⁻¹⁴ / [OH⁻] = 10⁻¹⁴ / 0.10 = 10⁻¹³ M
4. Calculate pH: pH = -log₁₀(10⁻¹³) = 13

The pH of a 0.10 M NaOH solution is 13, indicating it is strongly basic.

Interpreting Results

A pH of 13 for a 0.10 M NaOH solution indicates that the solution is highly basic. This is expected because NaOH is a strong base that completely dissociates in water, producing a high concentration of hydroxide ions.

In practical terms, a pH of 13 means the solution will:

• Feel slippery or soapy to the touch
• React strongly with acids to form water and a salt
• Have minimal dissolved metal ions due to precipitation