Chemistry: An Atoms-Focused Approach (Second Edition)
Chemistry: An Atoms-Focused Approach (Second Edition)
2nd Edition
ISBN: 9780393614053
Author: Thomas R. Gilbert, Rein V. Kirss, Stacey Lowery Bretz, Natalie Foster
Publisher: W. W. Norton & Company
Question
Book Icon
Chapter 15, Problem 15.62QA
Interpretation Introduction

To calculate:

a) pH of 0.0752M quinoline (C9H7N).

b) The OH- concentration of solution in part a.

Expert Solution & Answer
Check Mark

Answer to Problem 15.62QA

Solution:

a) pH=8.86

b) OH-=7.30×10-6 M

Explanation of Solution

1) Concept:

We can calculate Kb of quinolone using its pKb. Using the RICE table and Kb expression for reaction, we can calculate the hydroxide ion concentration. From this, we can get pOH and pH.

Kb=ProductcoefficentsReactantcoefficents

Here, Kb is equilibrium constant of base, Products is the concentration of products, Reactant is the concentration of reactants, and coefficient are the coefficient of reactants and product from the balanced reaction.

2) Formula:

i) Kb=ProductcoefficentsReactantcoefficents

ii) pKb= -logKb

iii) pH= -logH3O+

iv) pOH= -logOH-

v) pH+pOH=14

3) Given:

i) pKbof quinoline=9.15

ii) C9H7N=0.0752 M

4) Calculations:

RICE table for the given reaction:

Reaction C9H7Naq            +    H2Ol                         C9H7NH(aq)+  +         OH(aq)-
 C9H7N(M) C9H7NH+ (M) OH- (M)
Initial(I) 0.0752 0 0
Change(C) -x +x +x
Equilibrium(E) (0.0752-x) x x

pKb= -logKb

9.15= -logKb

Kb=10-9.15=7.08×10-10

Therefore, Kb expression for this reaction is

Kb=C9H7NH+OH-C9H7N=(x)(x)(0.0752-x)

7.08×10-10=x2(0.0752-x)

To solve for x, we make the simplifying assumption that x will be small compared to 0.0752 M because  C9H7Ninitial is 0.0752/(7.08×10-10) =1.06×108 times the Kb value, which is much greater than our 500× guideline.

7.08×10-10=x20.0752

7.08×10-10×0.0752=x2

x2=5.32×10-11

x=7.30×10-6 M

The ratio of 0.0752/(7.30×10-6)

OH-=x=7.30×10-6 M

pOH= -log7.30×10-6=5.14

pH+5.14=14

pH=14-5.14=8.86

Conclusion:

We got the value of Kb using the given value of pKb. Using the RICE table and Kb, we got the value pH of solution.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Chapter 15 Solutions

Chemistry: An Atoms-Focused Approach (Second Edition)

Ch. 15 - Prob. 15.11QACh. 15 - Prob. 15.12QACh. 15 - Prob. 15.13QACh. 15 - Prob. 15.14QACh. 15 - Prob. 15.15QACh. 15 - Prob. 15.16QACh. 15 - Prob. 15.17QACh. 15 - Prob. 15.18QACh. 15 - Prob. 15.19QACh. 15 - Prob. 15.20QACh. 15 - Prob. 15.21QACh. 15 - Prob. 15.22QACh. 15 - Prob. 15.23QACh. 15 - Prob. 15.24QACh. 15 - Prob. 15.25QACh. 15 - Prob. 15.26QACh. 15 - Prob. 15.27QACh. 15 - Prob. 15.28QACh. 15 - Prob. 15.29QACh. 15 - Prob. 15.30QACh. 15 - Prob. 15.31QACh. 15 - Prob. 15.32QACh. 15 - Prob. 15.33QACh. 15 - Prob. 15.34QACh. 15 - Prob. 15.35QACh. 15 - Prob. 15.36QACh. 15 - Prob. 15.37QACh. 15 - Prob. 15.38QACh. 15 - Prob. 15.39QACh. 15 - Prob. 15.40QACh. 15 - Prob. 15.41QACh. 15 - Prob. 15.42QACh. 15 - Prob. 15.43QACh. 15 - Prob. 15.44QACh. 15 - Prob. 15.45QACh. 15 - Prob. 15.46QACh. 15 - Prob. 15.47QACh. 15 - Prob. 15.48QACh. 15 - Prob. 15.49QACh. 15 - Prob. 15.50QACh. 15 - Prob. 15.51QACh. 15 - Prob. 15.52QACh. 15 - Prob. 15.53QACh. 15 - Prob. 15.54QACh. 15 - Prob. 15.55QACh. 15 - Prob. 15.56QACh. 15 - Prob. 15.57QACh. 15 - Prob. 15.58QACh. 15 - Prob. 15.59QACh. 15 - Prob. 15.60QACh. 15 - Prob. 15.61QACh. 15 - Prob. 15.62QACh. 15 - Prob. 15.63QACh. 15 - Prob. 15.64QACh. 15 - Prob. 15.65QACh. 15 - Prob. 15.66QACh. 15 - Prob. 15.67QACh. 15 - Prob. 15.68QACh. 15 - Prob. 15.69QACh. 15 - Prob. 15.70QACh. 15 - Prob. 15.71QACh. 15 - Prob. 15.72QACh. 15 - Prob. 15.73QACh. 15 - Prob. 15.74QACh. 15 - Prob. 15.75QACh. 15 - Prob. 15.76QACh. 15 - Prob. 15.77QACh. 15 - Prob. 15.78QACh. 15 - Prob. 15.79QACh. 15 - Prob. 15.80QACh. 15 - Prob. 15.81QACh. 15 - Prob. 15.82QACh. 15 - Prob. 15.83QACh. 15 - Prob. 15.84QACh. 15 - Prob. 15.85QACh. 15 - Prob. 15.86QACh. 15 - Prob. 15.87QACh. 15 - Prob. 15.88QACh. 15 - Prob. 15.89QACh. 15 - Prob. 15.90QACh. 15 - Prob. 15.91QACh. 15 - Prob. 15.92QACh. 15 - Prob. 15.93QACh. 15 - Prob. 15.94QACh. 15 - Prob. 15.95QACh. 15 - Prob. 15.96QACh. 15 - Prob. 15.97QACh. 15 - Prob. 15.98QACh. 15 - Prob. 15.99QACh. 15 - Prob. 15.100QACh. 15 - Prob. 15.101QACh. 15 - Prob. 15.102QACh. 15 - Prob. 15.103QACh. 15 - Prob. 15.104QACh. 15 - Prob. 15.105QACh. 15 - Prob. 15.106QACh. 15 - Prob. 15.107QACh. 15 - Prob. 15.108QACh. 15 - Prob. 15.109QACh. 15 - Prob. 15.110QA
Knowledge Booster
Background pattern image
Recommended textbooks for you
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781259911156
Author:Raymond Chang Dr., Jason Overby Professor
Publisher:McGraw-Hill Education
Text book image
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning
Text book image
Organic Chemistry
Chemistry
ISBN:9780078021558
Author:Janice Gorzynski Smith Dr.
Publisher:McGraw-Hill Education
Text book image
Chemistry: Principles and Reactions
Chemistry
ISBN:9781305079373
Author:William L. Masterton, Cecile N. Hurley
Publisher:Cengage Learning
Text book image
Elementary Principles of Chemical Processes, Bind...
Chemistry
ISBN:9781118431221
Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:WILEY