Concept explainers
Malic acid is a weak diprotic organic acid with Ka1 = 4.0 × 10−4 and Ka2 = 9.0 × 10−5.
- a Letting the symbol H2A represent malic acid, write the chemical equations that represent Ka1 and Ka2. Write the chemical equation that represents Ka1 × Ka2.
- b Qualitatively describe the relative concentrations of H2A, HA−, A2−, and H3O+ in a solution that is about one molar in malic acid.
- c Calculate the pH of a 0.0175 M malic acid solution and the equilibrium concentration of [H2A].
- d What is the A2− concentrationin in solutions b and c?
(a)
Interpretation:
Malic acid is weak diprotic acid with
Considering the symbol
Concept Introduction:
Acid ionization constant
The ionization of a weak acid
The equilibrium expression for the above reaction is given below.
Where,
Diprotic and polyprotic acids:
Acids having two or more hydrogen atoms are termed as diprotic or polyprotic acids. These acids lose one proton at a time by undergoing successive ionizations.
For diprotic acids, the successive ionization constants are designated as
For triprotic acids, the successive ionization constants are designated as
Answer to Problem 16.130QP
(a)
The chemical equation representing
The chemical equation representing
The chemical equation representing
Explanation of Solution
To Write: Considering the symbol
Given data:
Malic acid is a weak diprotic organic acid with
The chemical equation representing
The chemical equation representing
The chemical equation representing
The chemical equation representing
The chemical equation representing
The chemical equation representing
(b)
Interpretation:
Malic acid is weak diprotic acid with
Qualitatively the relative concentrations of
Concept Introduction:
Acid ionization constant
The ionization of a weak acid
The equilibrium expression for the above reaction is given below.
Where,
Diprotic and polyprotic acids:
Acids having two or more hydrogen atoms are termed as diprotic or polyprotic acids. These acids lose one proton at a time by undergoing successive ionizations.
For diprotic acids, the successive ionization constants are designated as
For triprotic acids, the successive ionization constants are designated as
Answer to Problem 16.130QP
The relative concentrations of
Explanation of Solution
To Give: Qualitatively the relative concentrations of
The relative concentrations of
The relative concentrations of
(c)
Interpretation:
Malic acid is weak diprotic acid with
The pH of 0.0175 M malic acid solution and the equilibrium concentration of
Concept Introduction:
Acid ionization constant
The ionization of a weak acid
The equilibrium expression for the above reaction is given below.
Where,
Diprotic and polyprotic acids:
Acids having two or more hydrogen atoms are termed as diprotic or polyprotic acids. These acids lose one proton at a time by undergoing successive ionizations.
For diprotic acids, the successive ionization constants are designated as
For triprotic acids, the successive ionization constants are designated as
Answer to Problem 16.130QP
The pH of 0.0175 M malic acid solution is 2.16
The equilibrium concentration of
Explanation of Solution
To Calculate: The pH of 0.0175 M malic acid solution and the equilibrium concentration of
The reaction is:
The
Substitute into the equilibrium constant expression
The pH is calculated as follows,
The concentration of
The pH of 0.0175 M malic acid solution is 2.61
The equilibrium concentration of
(d)
Interpretation:
Malic acid is weak diprotic acid with
The
Concept Introduction:
Acid ionization constant
The ionization of a weak acid
The equilibrium expression for the above reaction is given below.
Where,
Diprotic and polyprotic acids:
Acids having two or more hydrogen atoms are termed as diprotic or polyprotic acids. These acids lose one proton at a time by undergoing successive ionizations.
For diprotic acids, the successive ionization constants are designated as
For triprotic acids, the successive ionization constants are designated as
Answer to Problem 16.130QP
The
Explanation of Solution
To Calculate: The
Concentration of
Consider the second ionization of the acid for the calculation of
The
Substitute into the equilibrium constant expression
Assume y is small compared to
Similarly, the concentration of
The
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Chapter 16 Solutions
Bundle: General Chemistry, Loose-leaf Version, 11th + OWLv2 with Student Solutions Manual eBook, 4 terms (24 months) Printed Access Card
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