### Understanding Indicators and pKa**Problem Statement:**A certain indicator, HA, has a \( K_a \) value of \( 4.0 \times 10^{-7} \). The protonated form of the indicator is blue, and the ionized form is red.1. **Question**: What is the \( pK_a \) of the indicator? - **Answer Box**: (space provided)2. **Question**: What is the color of this indicator in a solution with \( \text{pH} = 4 \)? - **Options**: - ☐ red - ☐ purple - ☐ blue---### Explanation:- **Calculating pKa**: The \( pK_a \) is calculated using the formula \( pK_a = -\log(K_a) \).- **Color Indication**: - The color of an indicator in solution is based on the pH compared to its \( pK_a \). - If the pH is lower than the \( pK_a \), the solution is likely dominated by the **protonated form (blue)**. - If the pH is higher, the **ionized form (red)** is predominant. In this case, with \( pH = 4 \), you would compare it to the calculated \( pK_a \) to determine the color.

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A certain indicator, HA, has a K₂ value of 4.0 x 10-7. The protonated form of the indicator is blue and the ionized form is red. What is the pKa of the indicator? pK₂ = What is the color of this indicator in a solution with pH = 4? red purple blue

A certain indicator, HA, has a K₂ value of 4.0 x 10-7. The protonated form of the indicator is blue and the ionized form is red. What is the pKa of the indicator? pK₂ = What is the color of this indicator in a solution with pH = 4? red purple blue

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Acid Base Titration

An acid-base titration is the method of quantitative analysis for determining the concentration of an acid and base by exactly neutralizing it with a standard solution of base or acid having known concentration.

Question

### Understanding Indicators and pKa

**Problem Statement:**

A certain indicator, HA, has a \( K_a \) value of \( 4.0 \times 10^{-7} \). The protonated form of the indicator is blue, and the ionized form is red.

1. **Question**: What is the \( pK_a \) of the indicator?
- **Answer Box**: (space provided)

2. **Question**: What is the color of this indicator in a solution with \( \text{pH} = 4 \)?
- **Options**:
- ☐ red
- ☐ purple
- ☐ blue

---

### Explanation:

- **Calculating pKa**:
The \( pK_a \) is calculated using the formula \( pK_a = -\log(K_a) \).

- **Color Indication**:
- The color of an indicator in solution is based on the pH compared to its \( pK_a \).
- If the pH is lower than the \( pK_a \), the solution is likely dominated by the **protonated form (blue)**.
- If the pH is higher, the **ionized form (red)** is predominant.

In this case, with \( pH = 4 \), you would compare it to the calculated \( pK_a \) to determine the color.

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