Chapter 18 – Electrochemistry
Topic: Electrochemistry
99. Find the emf of the cell described by the cell diagram
Fe | Fe2+ (1.500M) || Au3+ (0.00400M) | Au.
100. Find the emf of the cell described by the cell diagram
Ni | Ni2+ (0.750 M) || Cu2+ (0.0500 M) | Cu.
Chapter 18 – Electrochemistry
101.
Consider the reaction Pb(s) + 2H+(aq) → Pb2+(aq) + H2(g). If the hydrogen gas pressure is maintained at 1.00 atm and the
lead(II) ion concentration is 0.025 M, find the pH at which this reaction is at equilibrium.
102.
Suppose the reaction Pb(s) + 2H+(aq) → Pb2+(aq) + H2(g) is carried out at pH = 4.00 and at a hydrogen gas pressure of 1.00
atm. The concentration of lead(II) ions that causes this reaction to be at equilibrium is
Chapter 18 – Electrochemistry
103. Which of these metals will be oxidized in hydrochloric acid under standard conditions at
25C?
104. Which of these metals will not be oxidized in hydrochloric acid under standard
conditions at 25C?
Chapter 18 – Electrochemistry
105. Which of these metals will reduce water to hydrogen in basic solution under standard
conditions?
106. Which of these metals will not reduce water to hydrogen in basic solution under standard
conditions?
Chapter 18 – Electrochemistry
107.
Consider the reaction 2Fe3+(aq) + Fe(s) 3Fe2+(aq). Find the equilibrium constant for this reaction at 25C.
108.
Consider the reaction Hg2+(aq) + Hg(l) Hg22+(aq). Find the equilibrium constant for this reaction at 25C.
Chapter 18 – Electrochemistry
109. Which of the following would be considered a fuel cell?
Chapter 18 – Electrochemistry
110. Which of the following would be considered a Lead Storage Battery?
Chapter 18 – Electrochemistry
111.
Select True or False: Under acidic conditions, the correctly balanced equation for the redox reaction Cr2O72-(aq) + I–(aq) →
Cr3+(aq) + IO3–(aq)
Is:
Cr2O72-(aq) + I–(aq) + 8H+(aq) → 2Cr3+(aq) + IO3–(aq) + 4H2O(l)
112.
Select True or False: Under acidic conditions, the correctly balanced redox reaction for Cu(s) + NO3–(aq) → Cu2+(aq) +
NO2(g) is:
Cu(s) + 2NO3–(aq) + 2H+(aq) → Cu2+(aq) + 2NO2(g) + H2O(l)
Chapter 18 – Electrochemistry
113.
Select True or False: Under acidic conditions, the correctly balanced redox reaction for
ClO2–(aq) → ClO2(g) + Cl–(aq) is:
5ClO2–(aq) + 4H+(aq) → 4ClO2(g) + Cl–(aq) + 2H2O(l)
114.
Select True or False: Under acidic conditions the correctly balanced redox reaction for
MnO4–(aq) + C2O42-(aq) → Mn2+(aq) + CO2(aq) is:
2MnO4–(aq) + 5C2O42-(aq) + 8H+(aq) → 2Mn2+(aq) + 10CO2(aq) + 8H2O(l)
115.
Select True or False: Under basic conditions, the correctly balanced redox reaction for
PO33-(aq) + MnO4–(aq) → PO43-(aq) + MnO2(s) is:
3PO33-(aq) + 2MnO4–(aq) + H2O(l) → 3PO43-(aq) + 2MnO2(s) + 2OH–(aq)
Chapter 18 – Electrochemistry
116.
Select True or False: Under basic conditions, the correctly balanced redox reaction for
CrO42-(aq) + SO32-(aq) → Cr(OH)3(s) + SO42-(aq) is
2CrO42-(aq) + 3SO32-(aq) + 5H2O(l) → 2Cr(OH)3(s) + 3SO42-(aq) + 2OH–(aq)
117.
Select True or False: The balanced overall redox equation for the following cell diagram:
Cr(s) | Cr3+(aq) || Sn4+(aq),Sn2+(aq) | Pt(s) is:
2Cr(s) + 3Sn4+(aq) → 2Cr3+(aq) + 3Sn2+(aq)
Chapter 18 – Electrochemistry
118.
Select True or False: The balanced overall redox equation for the following cell diagram:
Pt(s)| Cu+(aq) | Cu2+(aq) || Br2(l) | Br–(aq) | Pt(s) is
2Cu+(aq) + Pt(s) → 2Cu2+(aq) + Pt–(aq)
119.
What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the
overall redox equation:
3C2O42-(aq) + Cr2O72-(aq) + 14H+(aq) → 6CO2(g) + 2Cr3+(aq) + 7H2O(l)
Chapter 18 – Electrochemistry
120.
What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the
overall redox equation:
5Fe2+(aq) + MnO4–(aq) + 8H+(aq) → 5Fe3+(aq) + Mn2+(aq) + 4H2O(l)
121.
Gold can be electrochemically “plated” onto a less expensive metal by submerging the object in a solution of gold(III) and
applying an electric current to drive the following half-reaction:
Au3+ + 3e– → Au(s)
How many grams of gold will be formed if a current of 2.37 A is applied for 71 minutes?
Chapter 18 – Electrochemistry
122. What current is needed to deposit 0.500 g of chromium metal from a solution of Cr3+ in a
period of 1.00 hr?
123. Select True or False: H2(g) will form when Fe is placed in 1.0 M HCl.
124. Select True or False: H2(g) will form when Ag is placed in 1.0 M HCl.
125. Select True or False: H2(g) will form when Cu is placed in 1.0 M HCl.
126. Select True or False: H2(g) will form when Sn is placed in 1.0 M HCl.
127. When a solution of a certain gadolinium salt is electrolyzed with a current of 1.0 A for
2.0 h, 0.025 mol of Gd metal forms. Calculate the charge on the gadolinium ion in the salt.