Chapter 18 – Electrochemistry
66.
Calculate the cell voltage for the following reaction:
Cu2+ (0.010 M) + H2(1 atm) → Cu(s) + 2H+( pH = 7.0)
67.
Consider an electrochemical cell based on the spontaneous reaction
2AgCl(s) + Zn(s) → 2Ag(s) + 2Cl– + Zn2+.
If the zinc ion concentration is kept constant at 1 M, and the chlorine ion concentration is decreased from 1 M to 0.001 M,
the cell voltage should
Chapter 18 – Electrochemistry
68.
Consider an electrochemical cell involving the overall reaction
2AgBr(s) + Pb(s) → Pb2+ + 2Ag(s) + 2Br–.
Each half-reaction is carried out in a separate compartment. The anion included in the lead half-cell is NO3–. The cation in
the silver half-cell is K+. The two half-cells are connected by a KNO3 salt bridge. If [Pb2+] = 1.0 M, what concentration of Br–
ion will produce a cell emf of 0.25 V at 298 K?
Given: AgBr(s) + e– → Ag + Br–, E = +0.07 V.
69. The measured voltage of the cell Pt(s) | H2 (1.0 atm) | H+(aq) || Ag+(1.0 M) | Ag(s) is 1.02
V at 25C. Calculate the pH of the solution.
Chapter 18 – Electrochemistry
70.
The measured voltage of a cell in which the following reaction occurs is 0.96 V:
H2(g, 1.0 atm) + 2Ag+(aq, 1.0 M) → 2H+(aq, pH = ?) + 2Ag(s)
Calculate the pH of the H+(aq) solution.
71. If the measured voltage of the cell Zn(s) | Zn2+(aq) || Ag+(aq) | Ag(s) is 1.37 V when the
concentration of Zn2+ ion is 0.010 M, what is the Ag+ ion concentration?
Chapter 18 – Electrochemistry
72. Which one of the following reactions must be carried out in an electrolytic cell rather than
in a galvanic cell?
Chapter 18 – Electrochemistry
73. Which one of the following reactions must be carried out in an electrolytic cell rather than
in a galvanic cell?
Chapter 18 – Electrochemistry
74. Predict the products of the electrolysis of aqueous aluminum bromide AlBr3(aq).
(Balancing is not required.)
75. Predict the products of the electrolysis of aqueous potassium chloride KCl(aq).
Chapter 18 – Electrochemistry
76.
Calculate the minimum voltage required for the electrolysis of 1.0 M NaCl in neutral solution.
2H2O + 2Cl– (1.0 M) → H2(1 atm) + Cl2(1 atm) + 2OH– (1 10–7 M)
77. When an aqueous solution of AgNO3 is electrolyzed, a gas is observed to form at the
anode. The gas is
Chapter 18 – Electrochemistry
78. The half-reaction that occurs at the cathode during electrolysis of an aqueous sodium
iodide solution is
Chapter 18 – Electrochemistry
79. The half-reaction that occurs at the cathode during electrolysis of an aqueous CuCl2
solution is
Chapter 18 – Electrochemistry
80. The half-reaction occurring at the cathode during electrolysis of an aqueous copper(II)
iodide solution is
Chapter 18 – Electrochemistry
81. Under standard-state conditions, which of the following half-reactions occurs at the
cathode during the electrolysis of aqueous nickel sulfate at 25C?
Chapter 18 – Electrochemistry
82. The half-reaction that should occur at the anode during electrolysis of an aqueous
potassium bromide solution is
Chapter 18 – Electrochemistry
83. Which one of the following is consistent with a galvanic cell?
Chapter 18 – Electrochemistry
84. Which one of the following is consistent with a dead battery (an electrochemical cell at
equilibrium)?
85. How many coulombs of charge are required to cause reduction of 0.20 mole of Cr3+ to
Cr?
Chapter 18 – Electrochemistry
86. How many coulombs of charge are required to cause reduction of 0.25 mole of Cu2+ to
Cu?
87. A metal object is to be gold-plated by an electrolytic procedure using aqueous AuCl3
electrolyte. Calculate the number of moles of gold deposited in 3.0 min by a constant current
of 10. A.
Chapter 18 – Electrochemistry
88. A current of 0.80 A was applied to an electrolytic cell containing molten CdCl2 for 2.5
hours. Calculate the mass of cadmium metal deposited.
89. A current of 2.50 A was passed through an electrolytic cell containing molten CaCl2 for
4.50 hours. How many moles of calcium metal should be deposited?
Chapter 18 – Electrochemistry
90. How many grams of nickel would be electroplated by passing a constant current of 7.2 A
through a solution of NiSO4 for 90.0 min?
91. How many coulombs (C) of electrical charge must pass through an electrolytic cell to
reduce 0.44 mol Ca2+ ion to calcium metal?
Chapter 18 – Electrochemistry
92. How many grams of chromium would be electroplated by passing a constant current of
5.2 amperes through a solution containing CrCl3 for 45.0 min?
93. How many coulombs would be required to electroplate 35.0 grams of chromium by
passing an electrical current through a solution containing CrCl3?
94. How many minutes would be required to electroplate 25.0 grams of chromium by passing
a constant current of 4.80 amperes through a solution containing CrCl3?
95. How long will it take to produce 78 g of Al metal by the reduction of Al3+ in an
electrolytic cell with a current of 2.0 A?
Chapter 18 – Electrochemistry
96. Aluminum does not corrode as does iron, because
97. Iron objects such as storage tanks and underground pipelines can be protected from
corrosion by connecting them through a wire to a piece of
98. Which element is associated with the term “galvanized”?