What is the [H3O+] and the pH of a benzoic acid-benzoate buffer that consists of 0.12 M C6H₂COOH and 0.43 M C6H5COONa? (K₂ of benzoic acid = 6.3 × 10-5) Be sure to report your answer to the correct number of significant figures. [H₂O+]= pH x 10 M

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...
icon
Related questions
Question
**Buffer pH Calculation**

**Problem Statement:**
Determine the concentration of hydronium ions \([\text{H}_3\text{O}^+]\) and the pH of a benzoic acid-benzoate buffer with the following concentrations:
- 0.12 M \( \text{C}_6\text{H}_5\text{COOH} \) (benzoic acid)
- 0.43 M \( \text{C}_6\text{H}_5\text{COONa} \) (sodium benzoate)

**Given:**
- \( K_a \) of benzoic acid = \( 6.3 \times 10^{-5} \)

**Instructions:**
Calculate \([\text{H}_3\text{O}^+]\) and pH, ensuring that your answers reflect the correct number of significant figures.

**Calculations:**

\[ [\text{H}_3\text{O}^+] = \, \boxed{\phantom{00}} \times 10^{\boxed{\phantom{00}}} \, M \]

\[ \text{pH} = \, \boxed{\phantom{00}} \]  

This exercise will involve using the Henderson-Hasselbalch equation for buffer solutions:

\[ \text{pH} = \text{p}K_a + \log \left( \frac{[\text{A}^-]}{[\text{HA}]} \right) \]

Where:
- \( \text{p}K_a = -\log(K_a) \)
- \([\text{A}^-]\) is the concentration of the benzoate ion
- \([\text{HA}]\) is the concentration of benzoic acid

**Note:** The calculations here must take into account the significant figures based on the given concentrations and \( K_a \) value.
Transcribed Image Text:**Buffer pH Calculation** **Problem Statement:** Determine the concentration of hydronium ions \([\text{H}_3\text{O}^+]\) and the pH of a benzoic acid-benzoate buffer with the following concentrations: - 0.12 M \( \text{C}_6\text{H}_5\text{COOH} \) (benzoic acid) - 0.43 M \( \text{C}_6\text{H}_5\text{COONa} \) (sodium benzoate) **Given:** - \( K_a \) of benzoic acid = \( 6.3 \times 10^{-5} \) **Instructions:** Calculate \([\text{H}_3\text{O}^+]\) and pH, ensuring that your answers reflect the correct number of significant figures. **Calculations:** \[ [\text{H}_3\text{O}^+] = \, \boxed{\phantom{00}} \times 10^{\boxed{\phantom{00}}} \, M \] \[ \text{pH} = \, \boxed{\phantom{00}} \] This exercise will involve using the Henderson-Hasselbalch equation for buffer solutions: \[ \text{pH} = \text{p}K_a + \log \left( \frac{[\text{A}^-]}{[\text{HA}]} \right) \] Where: - \( \text{p}K_a = -\log(K_a) \) - \([\text{A}^-]\) is the concentration of the benzoate ion - \([\text{HA}]\) is the concentration of benzoic acid **Note:** The calculations here must take into account the significant figures based on the given concentrations and \( K_a \) value.
Expert Solution
Step 1

Recall the data from the question,

Molarity of C6H5COOH=0.12 M

Molarity of C6H5COONa=0.43 M

Ka of benzoic acid=6.3*10-5

Molarity of hydronium ion = ?

pH=?

steps

Step by step

Solved in 4 steps

Blurred answer
Knowledge Booster
Acid-Base Titrations
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
Chemistry
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY