Relative Half-Cell Potentials Assuming standard conditions, answer the following
ID: 558569 • Letter: R
Question
Relative Half-Cell Potentials Assuming standard conditions, answer the following questions. (Use the table of Standard Reduction Potentials for common Half-reactions from your text. If hydrogen is one of the reagents, assume acidic solution.) cf Table 11.1 on p 403 of Zumdahl 8th ed. yes Is H2(9) capable of reducing Ag (aq)? yesIs Cr3+(aq) capable of oxidizing Fe2+(aq) to Fe3+(aq)? no Is Fe2+(aq) capable of reducing Sn2+(aq) to Sn metal? yes Is Cr3+(aq) capable of oxidizing Fe2+(aq)? yes Is Sn metal capable of reducing Fe3+(aq) to Fe2+(aq)? yes Is VO2+ (aq) capable of oxidizing Fe2+(aq)?Explanation / Answer
1)
YES H2(g) capable of reducing Ag+(aq)
Write half- cell equation
2H+(aq) + 2e- H2(g) Eocell = +0.00V
Ag+(aq) + e- ----> Ag(s) Eocell +0.80V
Electrode potential of H2 is more negative than electrode potential of Ag. So for H2 it is easier to give electrons.H2 reduces Ag+ to Ag(s)
2)
NO Cr3+(aq) is not capable of oxidizing Fe2+(aq) to Fe3+
Write half- cell equation
Cr3+ --------> Cr2+ Eocell = -0.42V
Fe2+ ------> Fe3+ Eocell = +0.77V
Cr3+(aq) is not capable of oxidizing Fe2+(aq) because Cr3+ has a lower potential than Fe2+. Cr3+ cannot be reduced
3)
YES Fe2+(aq) capable of reducing Sn2+(aq) to Sn metal
Fe2+(aq) + 2e- --> Fe(s) Eocell -0.44 V
Sn2+(aq) + 2e- ----> Sn(s) Eocell -0.14V
For Fe2+ its electrode potential is more negative than Sn2+ , so Fe2+ equilibrium lies more on the left compared to Sn2+ and so it is able to reduce Sn2+
4)
NO Cr3+(aq) is not capable of oxidizing Fe2+(aq)
Write half- cell equation
Cr3+ --------> Cr2+ Eocell = -0.42V
Fe2+ ------> Fe3+ Eocell = +0.77V
Cr3+(aq) is not capable of oxidizing Fe2+(aq) because Cr3+ has a lower potential than Fe2+. Cr3+ cannot be reduced.
5)
YES Sn2+(aq) is capable of reducing Fe3+(aq) Fe2+(aq)
Sn²(aq) + 2e Sn(s) E°cell = -0.14 V
Fe³(aq) + e ----> Fe²(aq) E°cell = + 0.77 V
Electrode potential of Sn2+(aq is more negative than electrode potential of Fe3+ . So for Sn2+(aq) it is easier to give electrons and to reduces Fe3+(aq) Fe2+(aq).
6)
NO VO2+(aq) is not capable of oxidizing Fe2+(aq)
VO2(aq)+ ------------> V3+ Eocell + 0.34V
Fe2+(aq) + 2e- --> Fe3+ Eocell + 0.77 V
VO2+(aq) is not capable of oxidizing Fe2+(aq), because the standard potential of VO2(aq)+ is lower than that of Fe2+