Concept explainers
For alanine,
(a) 2.00.
(b) 6.00.
(c) 10.50.
What is the principal species at each pH?
(a)
Interpretation:
The value of
Concept introduction:
General formula of alanine is shown as follows:
The
Answer to Problem 29QAP
The principal species at
Explanation of Solution
Under equilibrium condition, the Zwitter ionic form of alanine is shown as follows:
Under acidic condition, oxygen atom accepts the proton Zwitter ion exists in cationic form.
Under basic condition, base abstracts proton form nitrogen atom and it forms the anionic form.
Dissociation of cation is represented as follows:
Dissociation of anion is represented as follows:
Given value of
At
So,
Take antilog both sides,
Here, Z is Zwitter ion and C is cationic form of Zwitter ion.
Here, Z is Zwitter ion and A is anionic form of Zwitter ion.
Therefore,
The principal species at
(b)
Interpretation:
The value of
Concept introduction:
General formula of alanine is shown as follows:
The
Answer to Problem 29QAP
The principal species at
Explanation of Solution
Under equilibrium condition zwitter ionic form of alanine is:
Under acidic condition oxygen atom accepts the proton zwitter ion exists in cationic form.
Under basic condition base abstracts proton form nitrogen atom and it forms the anionic form.
Dissociation of cation is-
Dissociation of anion is-
Given value of
At
So,
Take antilog both sides,
Here, Z is zwitter ion and C is cationic form of zwitter ion.
Here, Z is zwitter ion and A is anionic form of zwitter ion.
The principal species at
(c)
Interpretation:
The value of
Concept introduction:
General formula of alanine is shown as follows:
The
Answer to Problem 29QAP
The principal species at
Explanation of Solution
Under equilibrium condition zwitter ionic form of alanine is:
Under acidic condition oxygen atom accepts the proton zwitter ion exists in cationic form.
Under basic condition base abstracts proton form nitrogen atom and it forms the anionic form.
Dissociation of cation is-
Dissociation of anion is-
Given value of
At
So,
Take antilog both sides,
Here, Z is zwitter ion and C is cationic form of zwitter ion.
Here, Z is zwitter ion and A is anionic form of zwitter ion.
The principal species at
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