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6 Calculate The Ph of 0.100 M Kbro Solution K

Reviewed by Calculator Editorial Team

Calculating the pH of a 0.100 M potassium bromate (KBrO) solution involves understanding the dissociation of the weak acid and applying the Henderson-Hasselbalch equation. This guide provides a step-by-step explanation and includes a calculator for quick results.

Introduction

The pH of a solution is a measure of its acidity or basicity. For a weak acid like potassium bromate (KBrO), the pH depends on the concentration of the acid and its dissociation constant. This calculator helps determine the pH of a 0.100 M KBrO solution.

How to Calculate the pH

To calculate the pH of a 0.100 M KBrO solution, follow these steps:

  1. Identify the dissociation constant (Ka) of KBrO. For this calculation, we'll use Ka = 2.4 × 10-7.
  2. Use the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]).
  3. For a 0.100 M solution of KBrO, [HA] = 0.100 M and [A-] = 0 (since it's a weak acid).
  4. Calculate the pH using the values.

The Formula

The pH of a weak acid solution can be calculated using the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

Where:

  • pKa is the negative logarithm of the acid dissociation constant (-log Ka)
  • [A-] is the concentration of the conjugate base
  • [HA] is the concentration of the weak acid

Worked Example

Let's calculate the pH of a 0.100 M KBrO solution:

  1. Given Ka = 2.4 × 10-7, pKa = -log(2.4 × 10-7) ≈ 6.62.
  2. For a 0.100 M solution, [HA] = 0.100 M and [A-] = 0.
  3. Using the equation: pH = 6.62 + log(0/0.100).
  4. Since log(0) is undefined, we use the approximation that for very small [A-], pH ≈ pKa.
  5. Therefore, pH ≈ 6.62.

Note: For very dilute solutions of weak acids, the pH is approximately equal to the pKa of the acid.

FAQ

What is the pH of a 0.100 M KBrO solution?

The pH of a 0.100 M KBrO solution is approximately 6.62, which is close to the pKa of KBrO.

How does the concentration of KBrO affect the pH?

For very dilute solutions of weak acids like KBrO, the pH is approximately equal to the pKa of the acid. Increasing the concentration beyond very dilute levels would require a more detailed calculation.

What is the dissociation constant of KBrO?

The dissociation constant (Ka) of KBrO is approximately 2.4 × 10-7.