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Calculate Ph of 0.01 Solution of Sodium Hydroxide

Reviewed by Calculator Editorial Team

This calculator helps you determine the pH of a 0.01 molar solution of sodium hydroxide (NaOH). Sodium hydroxide is a strong base that completely dissociates in water, making it an ideal solution for pH calculations.

Introduction

The pH of a solution is a measure of its acidity or alkalinity. It's calculated using the concentration of hydrogen ions (H⁺) in the solution. For a 0.01 molar solution of sodium hydroxide, we can calculate the pH using the following steps:

  1. Determine the concentration of hydroxide ions (OH⁻)
  2. Calculate the concentration of hydrogen ions (H⁺)
  3. Use the pH formula to find the pH value

Since sodium hydroxide is a strong base, it completely dissociates in water, providing a known concentration of hydroxide ions.

How to Calculate pH

To calculate the pH of a 0.01 molar solution of sodium hydroxide:

  1. First, recognize that NaOH is a strong base that completely dissociates in water. This means that in a 0.01 M solution of NaOH, there are 0.01 moles of OH⁻ per liter of solution.
  2. The concentration of H⁺ ions can be found using the ionization product of water (Kw = 1.0 × 10⁻¹⁴ at 25°C).
  3. The pH is then calculated using the formula: pH = -log[H⁺]
pH = -log[H⁺] [H⁺] = Kw / [OH⁻] [OH⁻] = 0.01 M (for 0.01 M NaOH solution)

For a 0.01 M solution of NaOH, the pH calculation is straightforward because the concentration of OH⁻ is known and constant.

Example Calculation

Let's calculate the pH of a 0.01 M solution of NaOH step by step:

  1. Given: [NaOH] = 0.01 M (since it's a 0.01 molar solution)
  2. Since NaOH is a strong base, [OH⁻] = [NaOH] = 0.01 M
  3. Using Kw = 1.0 × 10⁻¹⁴ at 25°C:
  4. [H⁺] = Kw / [OH⁻] = (1.0 × 10⁻¹⁴) / (0.01) = 1.0 × 10⁻¹² M
  5. pH = -log[H⁺] = -log(1.0 × 10⁻¹²) = 12

Therefore, the pH of a 0.01 M solution of NaOH is 12.

Note: The pH of a 0.01 M solution of NaOH will always be 12 at 25°C because the concentration of hydroxide ions is fixed and the hydrogen ion concentration is determined by the ionization product of water.

Interpreting Results

A pH of 12 indicates that the solution is strongly alkaline. This means:

  • The solution will feel slippery to the touch
  • It will turn red litmus paper blue
  • It will react with acids to form water and a salt
  • It will not support the growth of most acid-loving microorganisms

In practical terms, a pH of 12 is much higher than neutral (pH 7) and is characteristic of strong base solutions like sodium hydroxide.

Frequently Asked Questions

What is the pH of a 0.01 M solution of NaOH?
The pH of a 0.01 M solution of NaOH is 12 at 25°C. This is because the strong base completely dissociates, providing a known concentration of hydroxide ions that determines the hydrogen ion concentration.
Does the pH of a NaOH solution change with concentration?
For strong bases like NaOH, the pH is primarily determined by the concentration of hydroxide ions. As long as the solution is sufficiently dilute, the pH will be 12 regardless of the exact concentration (as long as it's not so concentrated that it deviates from ideal behavior).
What is the relationship between pH and NaOH concentration?
For a strong base like NaOH, the pH is directly related to the concentration of hydroxide ions. The formula pH = 14 + log[OH⁻] can be used, but for a 0.01 M solution, it simplifies to pH = 12.
How does temperature affect the pH of a NaOH solution?
The ionization product of water (Kw) changes with temperature. At higher temperatures, Kw increases, which would slightly decrease the pH of a NaOH solution. However, this effect is usually small for most practical purposes.
What happens if I mix NaOH with water?
When you dissolve NaOH in water, it dissociates completely to form Na⁺ and OH⁻ ions. The concentration of hydroxide ions determines the pH, which will be 12 for a 0.01 M solution.