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Calculate The Ph of A 0.10 M Solution of Naoh

Reviewed by Calculator Editorial Team

This calculator helps you determine the pH of a 0.10 M (0.10 molar) solution of sodium hydroxide (NaOH). Understanding the pH of a solution is essential in chemistry, biology, and environmental science. The pH scale measures how acidic or basic a solution is, with values ranging from 0 (very acidic) to 14 (very basic).

Introduction

Sodium hydroxide (NaOH) is a strong base that completely dissociates in water to form hydroxide ions (OH⁻). When dissolved in water, it increases the concentration of OH⁻ ions, making the solution basic. The pH of a solution can be calculated using the concentration of hydroxide ions.

The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration ([H⁺]):

pH = -log₁₀[H⁺]

For a solution of a strong base like NaOH, the concentration of hydroxide ions ([OH⁻]) is equal to the initial concentration of the base because it fully dissociates. The relationship between [H⁺] and [OH⁻] is given by the ion product of water (Kw):

Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ at 25°C

For a 0.10 M solution of NaOH, [OH⁻] = 0.10 M. Using the ion product of water, we can find [H⁺] and then calculate the pH.

How to Calculate the pH

To calculate the pH of a 0.10 M solution of NaOH, follow these steps:

  1. Determine the concentration of hydroxide ions ([OH⁻]). For a strong base like NaOH, [OH⁻] is equal to the initial concentration of the base.
  2. Use the ion product of water (Kw) to find the concentration of hydrogen ions ([H⁺]).
  3. Calculate the pH using the negative logarithm of [H⁺].

Note: The ion product of water (Kw) is temperature-dependent. At 25°C, Kw = 1.0 × 10⁻¹⁴. For other temperatures, Kw changes, but we'll use 25°C for this calculation.

Worked Example

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

  1. Step 1: Determine [OH⁻]. For a 0.10 M solution of NaOH, [OH⁻] = 0.10 M.
  2. Step 2: Use Kw to find [H⁺].
    3. Kw = [H⁺][OH⁻] 1.0 × 10⁻¹⁴ = [H⁺] × 0.10 M [H⁺] = 1.0 × 10⁻¹⁴ / 0.10 M [H⁺] = 1.0 × 10⁻¹³ M
  3. Step 3: Calculate the pH.
    4. pH = -log₁₀[H⁺] pH = -log₁₀(1.0 × 10⁻¹³) pH = 13

The pH of a 0.10 M solution of NaOH is 13. This indicates a strongly basic solution.

Interpreting the Results

The pH of 13 for a 0.10 M solution of NaOH indicates a very basic solution. Here's what this means:

  • The solution has a high concentration of hydroxide ions (OH⁻), which makes it basic.
  • A pH of 13 is very close to the maximum pH of 14, which is the theoretical maximum for a basic solution.
  • This solution would react strongly with acids and would not be suitable for many biological or chemical processes that require neutral or slightly acidic conditions.

Important: Always handle NaOH solutions with caution. They are corrosive and can cause chemical burns. Wear appropriate protective equipment when working with strong bases.

Frequently Asked Questions

What is the pH of a 0.10 M solution of NaOH?
The pH of a 0.10 M solution of NaOH is 13. This indicates a strongly basic solution.
Why is the pH of a NaOH solution high?
The pH is high because NaOH is a strong base that completely dissociates in water, increasing the concentration of hydroxide ions (OH⁻), which makes the solution basic.
How does temperature affect the pH calculation?
The ion product of water (Kw) is temperature-dependent. At 25°C, Kw = 1.0 × 10⁻¹⁴. For other temperatures, Kw changes, which would affect the pH calculation. Our calculator uses 25°C by default.
Is NaOH a strong or weak base?
NaOH is a strong base because it completely dissociates in water to form hydroxide ions (OH⁻).
What safety precautions should I take when working with NaOH solutions?
Always wear appropriate protective equipment, including gloves and goggles, when working with NaOH solutions. They are corrosive and can cause chemical burns.