Consider the reaction below at 25°C:
Use Table 17.1 to answer the following questions. Support your answers with calculations.
(a) Is the reaction spontaneous at standard conditions?
(b) Is the reaction spontaneous at a pH of 2.00 with all other ionic species at 0.100 M?
(c) Is the reaction spontaneous at a pH of 5.00 with all other ionic species at 0.100 M?
(d) At what pH is the reaction at equilibrium with all other ionic species at 0.100 M?
(a)
Interpretation:
The spontaneity of the reaction at standard conditions needs to be determined.
Concept introduction:
The standard electrode potential
where,
Answer to Problem 73QAP
The reaction is spontaneous
Explanation of Solution
The cell reaction is as follows.
Step 1: Write the two half-cell reactions.
Oxidation half-reaction (Anode):
Reduction half-reaction (Cathode):
Step 2: Calculation of standard electrode potential
Here,
From equation
Thus, the reaction is spontaneous
(b)
Interpretation:
The spontaneity of the reaction at a
Concept introduction:
The formula of Nernst equation is used to calculate the spontaneity of the reaction, given by,
where,
Answer to Problem 73QAP
The reaction is spontaneous
Explanation of Solution
Calculation of reaction quotient
From Nernst equation,
Put the values of
Thus, the reaction is spontaneous
(c)
Interpretation:
The spontaneity of the reaction at a
Concept introduction:
The formula of Nernst equation is used to calculate the spontaneity of the reaction, given by,
where,
Answer to Problem 73QAP
The reaction is non-spontaneous
Explanation of Solution
Calculation of reaction quotient
From Nernst equation,
Put the values of
Thus, the reaction is non-spontaneous
(d)
Interpretation:
The
Concept introduction:
The relation between
Answer to Problem 73QAP
At equilibrium,
Explanation of Solution
From Nernst equation,
Put the values of
Now,
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Chapter 17 Solutions
Chemistry: Principles and Reactions
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