Exploring Chemical Analysis
Exploring Chemical Analysis
5th Edition
ISBN: 9781429275033
Author: Daniel C. Harris
Publisher: Macmillan Higher Education
Question
Book Icon
Chapter 15, Problem 15.24P

(a)

Interpretation Introduction

Interpretation:

Expression for ion selective electrode for La3+ has to be written.

Concept Introduction:

Liquid- ion-selective electrode is composed of the hydrophobic ion-selective membrane that is essentially an organic polymer. This thin membrane is filled with a viscous ion exchanger solution. The purpose of this solution is to selectively bond the analyte ion. Selectivity of the bound analyte can be mathematically measured with the use of selectivity coefficient.

Potential difference for ion selective electrode is evaluated by expression as follows:

  E=0.05916n[log([C+]outer 2)log([C+]outer 1)]

Here,

[C+]outer 2 denotes concentration of analyte solution 2.

[C+]inner denotes concentration of analyte solution 1.

n denotes charge on analyte.

E denotes potential difference.

(a)

Expert Solution
Check Mark

Explanation of Solution

Expression to compute potential of ion selective electrode is given as follows:

  E=constant+β(0.05916)nlog[Xn+]        (1)

Substitute La3+ for Xn+ and 3 for n in equation (1).

  E=constant+β(0.05916)3log[La3+]        (2)

(b)

Interpretation Introduction

Interpretation:

Change in voltage in millivolts when electrode is transferred from 1.00×104 M solution to 1.00×103 M solution has to be calculated.

Concept Introduction:

Refer to part (a).

(b)

Expert Solution
Check Mark

Explanation of Solution

Expression to compute potential difference for ion selective electrode is evaluated by expression as follows:

  E=0.05916n[log([C+]outer 2)log([C+]outer 1)]        (3)

Substitute 3 for n, 1.00×103 M for [C+]outer 2 and 1.00×104 M for [C+]outer 1 in equation (3).

  E=0.059163[log(1.00×103)log(1.00×104)]=0.059163(1)=0.01972 V

Conversion factor to convert V to mV is as follows:

  1 mV=103 V

Hence potential of 0.01972 V is converted mV as follows:

  Voltage=(0.01972 V)(1 mV103 V)=19.7 mV

Hence voltage change is 19.7 mV.

(c)

Interpretation Introduction

Interpretation:

Change in voltage in millivolts when electrode is transferred from 2.36×104 M solution to 4.44×103 M solution has to be calculated.

Concept Introduction:

Refer to part (a).

(c)

Expert Solution
Check Mark

Explanation of Solution

Expression to compute potential difference for ion selective electrode is evaluated by expression as follows:

  E=0.05916n[log([C+]outer 2)log([C+]outer 1)]        (3)

Substitute 3 for n, 4.44×103 M for [C+]outer 2 and 2.36×104 M for [C+]outer 1 in equation (3).

  E=0.059163[log(4.44×103)log(2.36×104)]=0.0251 V

Conversion factor to convert V to mV is as follows:

  1 mV=103 V

Hence potential of 0.0251 V is converted mV as follows:

  Voltage=(0.0251 V)(1 mV103 V)=25.1 mV

Hence voltage when Fe3+ is added is 25.1 mV.

(d)

Interpretation Introduction

Interpretation:

Voltage when Fe3+ is added has to be calculated.

Concept Introduction:

Refer to part (a).

(d)

Expert Solution
Check Mark

Explanation of Solution

Substitute 1.00×104 M for [La3+] , 1 for β and 0.1 V for E in equation (1).

  0.1=constant+β(0.05916)3log(1×104)constant=0.17888

Expression to compute response of ion selective electrode due to Fe3+ interference is given as follows:

  E=constant+β(0.05916)3log([La3+]+kLa3+, Fe3+[Fe3+])        (4)

Substitute0.17888 for constant, 1.00×104 M for [La3+], 0.010 M for [Fe3+],1/1200 for kLa3+, Fe3+ and 1 for β in equation (4).

  E=0.17888+0.059163log(1.00×104+(11200)(0.01 M))=+0.10068 V0.1007 V                                

Hence potential of 0.1007 V is converted mV as follows:

  Voltage=(0.1007 V)(1 mV103 V)=100.7 mV

Hence voltage when Fe3+ is added is 100.7 mV.

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!
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