   # Which is the stronger of the following two acids? (a) benzoic acid, C 6 H 5 CO 2 H, p K a = 4.20 (b) 2-chlorobenzoic acid, ClC 6 H 4 CO 2 H, p K a = 2.90 ### Chemistry & Chemical Reactivity

9th Edition
John C. Kotz + 3 others
Publisher: Cengage Learning
ISBN: 9781133949640

#### Solutions

Chapter
Section ### Chemistry & Chemical Reactivity

9th Edition
John C. Kotz + 3 others
Publisher: Cengage Learning
ISBN: 9781133949640
Chapter 16, Problem 29PS
Textbook Problem
1 views

## Which is the stronger of the following two acids? (a) benzoic acid, C6H5CO2H, pKa = 4.20 (b) 2-chlorobenzoic acid, ClC6H4CO2H, pKa = 2.90

Interpretation Introduction

Interpretation:  The comparison of acidic strength of the given acids has to be done by using their given pKa values.

Concept introduction: In aqueous solution an acid undergoes ionization. The ionization of an acid is can be expressed in terms of equilibrium constant. The quantitative measurement tells about the strength of the acid. Higher the value of Ka stronger will be the acid. The acid dissocition can be represented as following equilibrium,

HA(aq)+  H2O(l) H3O+(aq)+ A1(aq)

The dissociation constant for the acid is Ka,

Ka=[H3O+][A][HA]

For simplifications, pKa value is used to find the acidic strength of acid which is calculated by taking negative logarithm of Ka.

pKa=log(Ka)

The lower value of pKa of an acid, stronger will be the acid. Thus on comparing the pKa value it can be determined which acid is stronger one among them.

### Explanation of Solution

On comparing the pKa values of both acid it is found that 2-Chlorobenzoic acid (ClC6H4CO2H) has lower value of pKa than Benzoic acid(C6H5CO2H). Thus, 2-Chlorobenzoic acid (ClC6H4CO2H) is stronger acid than Benzoic acid(C6H5CO2H).

Given: The pKa values of both acids are given for Benzoic acid(C6H5CO2H)pKa value is 4.20 and for 2-Chlorobenzoic acid(ClC6H4CO2H)pKa value is 2.90. The Ka values for the acids are calculated as,

pKa=log(Ka)Ka=10(pKa)

pKa value for Benzoic acid(C6H5CO2H) is 4

### 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
"Red flags" that can help to identify nutrition quackery include a. enticingly quick and simple answers to comp...

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

List the differences between mitosis and meiosis in the following chart:

Human Heredity: Principles and Issues (MindTap Course List)

Even a small loss of body weight can improve OA.

Nutrition Through The Life Cycle

22-18 Draw the structures of L- and D-valine.

Introduction to General, Organic and Biochemistry

A series RLC circuit has a resistance of 45.0 and an impedance of 75.0 . What average power is delivered to th...

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