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Problem 46
A voltaic cell consists of a strip of cadmium metal in a solution of Cd(NO3)2 in one beaker, and in the other beaker a platinum electrode is immersed in a NaCl solution, with Cl2 gas bubbled around the electrode. A salt bridge connects the two beakers. (a) Which electrode serves as the anode, and which as the cathode? (b) Does the Cd electrode gain or lose mass as the cell reaction proceeds? (c) Write the equation for the overall cell reaction.
Problem 47a,b,c
From each of the following pairs of substances, use data in Appendix E to choose the one that is the stronger reducing agent: (a) Fe(s) or Mg(s) (b) Ca(s) or Al(s) (c) H2(g, acidic solution) or H2S(g)
- From each of the following pairs of substances, use data in Appendix E to choose the one that is the stronger oxidizing agent: (a) Cl2(g) or Br2(l) (b) Zn2+(aq) or Cd2+(aq) (c) Cl-(aq) or ClO3-(aq) (d) H2O2(aq) or O3(g)
Problem 48
Problem 49a,b,c
By using the data in Appendix E, determine whether each of the following substances is likely to serve as an oxidant or a reductant: (a) Cl2(g), (b) MnO4- (aq, acidic solution), (c) Ba(s)
Problem 49d
By using the data in Appendix E, determine whether each of the following substances is likely to serve as an oxidant or a reductant: (d) Zn(s)
Problem 50
Is each of the following substances likely to serve as an oxidant or a reductant: (a) Ce3+(aq) (b) Ca(s) (c) ClO3-(aq) (d) N2O5(g)?
Problem 51a
(a) Assuming standard conditions, arrange the following in order of increasing strength as oxidizing agents in acidic solution: Cr2O72-, H2O2, Cu2+, Cl2, O2.
Problem 51b
(b) Arrange the following in order of increasing strength as reducing agents in acidic solution: Zn, I-, Sn2+, H2O2, Al.
- Based on the data in Appendix E, (a) which of the following is the strongest oxidizing agent, and which is the weakest in acidic solution: Br2, H2O2, Zn, Cr2O72-?
Problem 52
- The standard reduction potential of Eu2+(aq) is -0.43 V. Using Appendix E, which of the following substances is capable of reducing Eu3+(aq) to Eu2+(aq) under standard conditions: Al, Co, H2O2, N2H5+, H2C2O4?
Problem 53
Problem 55a
Given the following reduction half-reactions:
Fe3+(aq) + e- → Fe2+(aq) E°red = +0.77 V
S2O62-(aq) + 4 H+(aq) + 2 e- → 2 H2SO3(aq) E°red = +0.60 V
N2O(g) + 2 H+(aq) + 2 e- → N2(g) + H2O(l) E°red = -1.77 V
VO2+(aq) + 2 H+(aq) + e- → VO2+ + H2O(l) E°red = +1.00 V
(a) Write balanced chemical equations for the oxidation of Fe2+(aq) by S2O62-(aq), by N2O(aq), and by VO2+(aq).
Problem 55b
Given the following reduction half-reactions:
Fe3+(aq) + e- → Fe2+(aq) E°red = +0.77 V
S2O62-(aq) + 4 H+(aq) + 2 e- → 2 H2SO3(aq) E°red = +0.60 V
N2O(g) + 2 H+(aq) + 2 e- → N2(g) + H2O(l) E°red = -1.77 V
VO2+(aq) + 2 H+(aq) + e- → VO2+ + H2O(l) E°red = +1.00 V
(b) Calculate ∆G° for each reaction at 298 K.
Problem 56
Given the following reduction half-reactions:
Fe3+(aq) + e- → Fe2+(aq) E°red = +0.77 V
S2O62-(aq) + 4 H+(aq) + 2 e- → 2 H2SO3(aq) E°red = +0.60 V
N2O(g) + 2 H+(aq) + 2 e- → N2(g) + H2O(l) E°red = -1.77 V
VO2+(aq) + 2 H+(aq) + e- → VO2+ + H2O(l) E°red = +1.00 V
(c) Calculate the equilibrium constant K for each reaction at 298 K.
Problem 56a
For each of the following reactions, write a balanced equation, calculate the standard emf, calculate ∆G° at 298 K, and calculate the equilibrium constant K at 298 K. (a) Aqueous iodide ion is oxidized to I21s2 by Hg22+1aq2.
Problem 56b
For each of the following reactions, write a balanced equation, calculate the standard emf, calculate ∆G° at 298 K, and calculate the equilibrium constant K at 298 K. (b) In acidic solution, copper(I) ion is oxidized to copper(II) ion by nitrate ion.
Problem 56c
For each of the following reactions, write a balanced equation, calculate the standard emf, calculate ∆G° at 298 K, and calculate the equilibrium constant K at 298 K. (c) In basic solution, Cr1OH231s2 is oxidized to CrO42-1aq2 by ClO-1aq2.
- If the equilibrium constant for a two-electron redox reaction at 298 K is 1.5 * 10⁻⁴, calculate the corresponding ∆G° and E°.
Problem 57
Problem 57d
From each of the following pairs of substances, use data in Appendix E to choose the one that is the stronger reducing agent: (d) BrO3-1aq2 or IO3-1aq2
- If the equilibrium constant for a one-electron redox reaction at 298 K is 8.7 * 10^4, calculate the corresponding ∆G° and E°.
Problem 58
Problem 59
Using the standard reduction potentials listed in Appendix E, calculate the equilibrium constant for each of the following reactions at 298 K:
(a) Fe(s) + Ni2+(aq) → Fe2+(aq) + Ni(s)
(b) Co(s) + 2 H+(aq) → Co2+(aq) + H2(g)
(c) 10 Br-(aq) + 2 MnO4-(aq) + 16 H+(aq) → 2 Mn2+(aq) + 8 H2O(l) + 5 Br2(l)
- Using the standard reduction potentials listed in Appendix E, calculate the equilibrium constant for each of the following reactions at 298 K: (a) Cu(s) + 2 Ag+(aq) → Cu2+(aq) + 2 Ag(s) (b) 3 Ce4+(aq) + Bi(s) + H2O(l) → 3 Ce3+(aq) + BiO+(aq) + 2 H+(aq) (c) N2H5+(aq) + 4 Fe(CN)6^3- (aq) → N2(g) + 5 H+(aq) + 4 Fe(CN)6^4-(aq)
Problem 60
Problem 61a
A cell has a standard cell potential of +0.177 V at 298 K. What is the value of the equilibrium constant for the reaction
(a) if n = 1?
Problem 61b,c
A cell has a standard cell potential of +0.177 V at 298 K. What is the value of the equilibrium constant for the reaction (b) if n = 2? (c) if n = 3?
Problem 62
At 298 K a cell reaction has a standard cell potential of +0.17 V. The equilibrium constant for the reaction is 5.5 × 105. What is the value of n for the reaction?
- A voltaic cell is based on the reaction Sn(s) + I2(s) → Sn2+(aq) + 2 I-(aq). Under standard conditions, what is the maximum electrical work, in joules, that the cell can accomplish if 75.0 g of Sn is consumed?
Problem 63
- (a) In the Nernst equation, what is the numerical value of the reaction quotient, Q, under standard conditions? (b) Can the Nernst equation be used at temperatures other than room temperature?
Problem 65
- A voltaic cell is constructed with all reactants and products in their standard states. Will the concentration of the reactants increase, decrease, or remain the same as the cell operates?
Problem 66
Problem 68
A voltaic cell utilizes the following reaction: Al1s2 + 3 Ag+1aq2 ¡ Al3+1aq2 + 3 Ag1s2 What is the effect on the cell emf of each of the following changes? (a) Water is added to the anode half-cell, diluting the solution.
Problem 69b,c
A voltaic cell is constructed that uses the following reaction and operates at 298 K: Zn(s) + Ni2+(aq) → Zn2+(aq) + Ni(s) (b) What is the emf of this cell when [Ni2+] = 3.00 M and [Zn2+] = 0.100 M? (c) What is the emf of the cell when [Ni2+] = 0.200 M and [Zn2+] = 0.900 M?
- A voltaic cell utilizes the following reaction and operates at 298 K: 3 Ce⁴⁺(aq) + Cr(s) → 3 Ce³⁺(aq) + Cr³⁺(aq) (b) What is the emf of this cell when [Ce⁴⁺] = 3.0 M, [Ce³⁺] = 0.10 M, and [Cr³⁺] = 0.010 M? (c) What is the emf of the cell when [Ce⁴⁺] = 0.010 M, [Ce³⁺] = 2.0 M, and [Cr³⁺] = 1.5 M?
Problem 70