Calculate [H+] and pH in a solution in which lactic acid, HC3H5O3, is 0.250 M and the lactate ion, C3H5O3-, is
(a) 0.250 M (b) 0.125 M
(c) 0.0800 M (d) 0.0500 M
(a)
Interpretation:
The
Concept Introduction :
For an acid dissociation reaction, the
Here,
From the hydrogen ion concentration, the pH of the solution can be calculated as follows:
Answer to Problem 9QAP
Explanation of Solution
The equilibrium reaction is as follows:
The expression of Ka for this reaction is as follows:
The above expression can be written as follows:
The Ka value of lactic acid HC3H5O3 is 1.4 x 10-4, the concentrated of lactic acid (HC3H5O3) is 0.250 M, and for lactate ion C3H5O3- is 0.250 M.
Substitute these values in the above expression as follows:
=
=
Now, the pH of the solution can be calculated by using the [H+] as follows:
So, the pH of the solution is 3.85 and
(b)
Interpretation:
The
Concept Introduction :
For an acid dissociation reaction, the
Here,
From the hydrogen ion concentration, the pH of the solution can be calculated as follows:
Answer to Problem 9QAP
Explanation of Solution
The equilibrium reaction is as follows:
The expression of Ka for this reaction is as follows:
The above expression can be written as follows:
The Ka value of lactic acid HC3H5O3 is 1.4 x 10-4, the concentrated of lactic acid (HC3H5O3) is 0.250 M, and for lactate ion C3H5O3- is 0.125 M.
Substitute these values in the above expression as follows:
=
=
Now, the pH of the solution can be calculated by using the [H+] as follows:
pH = -log10 [H+]
= -log10 [2.8 x 10-4]
= 3.55
So, the pH of the solution is 3.55 and [H+] is
(C)
Interpretation:
The
Concept Introduction :
For an acid dissociation reaction, the
Here,
From the hydrogen ion concentration, the pH of the solution can be calculated as follows:
Answer to Problem 9QAP
Explanation of Solution
The equilibrium reaction is as follows:
The expression of Ka for this reaction is as follows:
The above expression can be written as follows:
The Ka value of lactic acid HC3H5O3 is 1.4 x 10-4, the concentrated of lactic acid (HC3H5O3) is 0.250 M, and for lactate ion C3H5O3- is 0.0800 M.
Substitute these values in the above expression as follows:
=
=
Now, the pH of the solution can be calculated by using the [H+] as follows:
pH = -log10 [H+]
= -log10
= 3.36
So, the pH of the solution is 3.36 and [H+] is
(d)
Interpretation:
The
Concept Introduction :
For an acid dissociation reaction, the
Here,
From the hydrogen ion concentration, the pH of the solution can be calculated as follows:
Answer to Problem 9QAP
Explanation of Solution
The equilibrium reaction is as follows:
The expression of Ka for this reaction is as follows:
The above expression can be written as follows:
The Ka value of lactic acid HC3H5O3 is 1.4 x 10-4, the concentrated of lactic acid (HC3H5O3) is 0.250 M, and for lactate ion C3H5O3- is 0.0500 M.
Substitute these values in the above expression as follows:
=
=
Now, the pH of the solution can be calculated by using the [H+] as follows:
pH = -log10 [H+]
= -log10
= 3.15
So, the pH of the solution is 3.15 and [OH-] is
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Chapter 14 Solutions
OWLv2 with Student Solutions Manual eBook for Masterton/Hurley's Chemistry: Principles and Reactions, 8th Edition, [Instant Access], 4 terms (24 months)
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