   # Calculate the pH at the halfway point and at the equivalence point for each of the following titrations. a. 100.0 mL of 0.10 M HC 7 H 5 O 2 ( K a = 6.4 × 10 −5 ) titrated by 0.10 M NaOH b. 100.0 mL of 0.10 M C 2 H 5 NH 2 ( K b = 5.6 × 10 −4 ) titrated by 0.20 M HNO 3 c. 100.0 mL of 0.50 M HCl titrated by 0.25 M NaOH ### Chemistry: An Atoms First Approach

2nd Edition
Steven S. Zumdahl + 1 other
Publisher: Cengage Learning
ISBN: 9781305079243

#### Solutions

Chapter
Section ### Chemistry: An Atoms First Approach

2nd Edition
Steven S. Zumdahl + 1 other
Publisher: Cengage Learning
ISBN: 9781305079243
Chapter 14, Problem 65E
Textbook Problem
1 views

## Calculate the pH at the halfway point and at the equivalence point for each of the following titrations.a. 100.0 mL of 0.10 M HC7H5O2 (Ka = 6.4 × 10−5) titrated by 0.10 M NaOHb. 100.0 mL of 0.10 M C2H5NH2 (Kb = 5.6 × 10−4) titrated by 0.20 M HNO3c. 100.0 mL of 0.50 M HCl titrated by 0.25 M NaOH

(a)

Interpretation Introduction

Interpretation: The halfway point and the equivalence point pH for each of the given titrations are to be calculated.

Concept introduction: The pH value is defined as a figure that is used to express the acidity or basicity of a solution by using the logarithmic scale on which 7 is a neutral. The values lower than 7 shows acidic or greater than 7 shows basic behavior of the solution.

To determine: The halfway point and the equivalence point pH for the given titration.

### Explanation of Solution

Explanation

Given

Concentration of HC7H5O2 is 0.10M .

Volume of the solution is 100mL .

Concentration of NaOH is 0.10M

According to the half-way titration, the volume of the base consumed is half of the equivalence point. Volume of the base is calculated by using the expression,

M1V1=M2V2

Where,

• M1 is the concentration of HC7H5O2 .
• M2 is the concentration of NaOH .
• V1 is the volume of HC7H5O2 solution.
• V2 is the volume of NaOH solution.

Substitute the values of M1 , V1 , and M2 in the above expression to calculate the volume of NaOH solution.

M1V1=M2V20.10M×100mL=0.10M×V2V2=100mL

The volume of the base at the equivalence point is V2=100mL .

The volume of the base at the half-way point is 50mL .

The reaction between C6H5COOH and NaOH at the half-way equivalence point is,

C6H5COOH+NaOHC6H5COONa+H2O0.01mole0.005mole0.005mole

The pH at half-way point is calculated by using the formula,

pH=pKa+log[Salt][Acid]

The pKa of benzoic acid is 4.20 .

Substitute the values of pKa and concentration of salt and acid in the above formula to calculate the pH at half-way point.

pH=4.20+log[0.005][0.005]=4.20_

Hence, the pH at the half-way equivalence point is 4.20_ .

At equivalence point, the reaction between C6H5COOH and NaOH is,

C6H5COOH+NaOHC6H5COONa+H2O0

(b)

Interpretation Introduction

Interpretation: The halfway point and the equivalence point pH for each of the given titrations are to be calculated.

Concept introduction: The pH value is defined as a figure that is used to express the acidity or basicity of a solution by using the logarithmic scale on which 7 is a neutral. The values lower than 7 shows acidic or greater than 7 shows basic behavior of the solution.

To determine: The halfway point and the equivalence point pH for the given titration.

(c)

Interpretation Introduction

Interpretation: The halfway point and the equivalence point pH for each of the given titrations are to be calculated.

Concept introduction: The pH value is defined as a figure that is used to express the acidity or basicity of a solution by using the logarithmic scale on which 7 is a neutral. The values lower than 7 shows acidic or greater than 7 shows basic behavior of the solution.

To determine: The halfway point and the equivalence point pH for the given titration.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Find more solutions based on key concepts
Fried banana or vegetable snack chips make a healthy everyday snack choice for vegetarians. T F

Nutrition: Concepts and Controversies - Standalone book (MindTap Course List)

Make the following temperature conversions:

Chemistry & Chemical Reactivity

What is the first element of the scientific method?

An Introduction to Physical Science

Does the cell cycle refer to mitosis as well as meiosis?

Human Heredity: Principles and Issues (MindTap Course List)

What is the difference between sea islands and barrier islands?

Oceanography: An Invitation To Marine Science, Loose-leaf Versin

A sphere of radius R = 1.00 m surrounds a particle with charge Q = 50.0 C located at its center as shown in Fig...

Physics for Scientists and Engineers, Technology Update (No access codes included)

What does the word visual mean in apparent visual magnitude?

Foundations of Astronomy (MindTap Course List) 