Solve Selective Reduction of Sn4+ to Sn2+ w/o Sn2+ to Sn

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The discussion revolves around identifying anodic half-reactions that allow for the spontaneous reduction of Sn4+ to Sn2+ without further reducing Sn2+ to Sn. The user calculated the oxidation potentials for various reactions and found that Pb, Sn2+, and Fe yield positive Ecell values for the desired reaction. However, they questioned whether an Ecell of zero, as seen in the reaction Sn to Sn2+, could be considered spontaneous. The conversation highlights the importance of understanding standard reduction potentials and the criteria for spontaneity in galvanic cells. Clarification on the definition of spontaneity in relation to equilibrium is also sought.
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Homework Statement



Given: Sn4+ + 2e- --->Sn2+ Estandard=+0.15V
For a galvanic cell under standard condition, which of the following anodic half reaction would produce at the cathode a spontaneous reduction of Sn4+ to Sn2+ but NOT Sn2+ to Sn.

Pb --> Pb2+ + 2e-
Sn2+ --> Sn4+ + 2e-
Pb + SO42- --> PbSO4 + 2e-
Sn --> Sn2+ + 2e-
Fe --> Fe3+ + 3e-
Ni --> Ni2+ + 2e-

The Attempt at a Solution



I found the oxidation potential for all of the above reactions:

+0.126
-0.139
+0.355
+0.141
+0.036
+0.236, respectively

For a spontaneous reaction, the Ecell has to be positive. I calculated the Ecell for each of those reactions with Sn4+ + 2e- --->Sn2+ Estandard=+0.15V and with Sn2+ + 2e---->Sn

I found that Pb --> Pb2+ + 2e-, Sn2+ --> Sn4+ + 2e-, and Fe --> Fe3+ + 3e- are the only three that produce a Ecell that is positive for Sn4+ to Sn2+ and NOT Sn2+ to Sn

but for Sn --> Sn2+ + 2e- reacting with Sn2+ + 2e---->Sn, the Ecell is obviously equation to zero, would that considered to be spontaneous??

can someone check if I am doing this right?

Thanks a lot =)
 
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am I on the right track here?
 
do u go to the UoW? :)
 
what is "UoW"?
 
lol i guess not


by the way in ur questions do u have one like this..

Selective Oxidation (not reduction)

--------------------------------------------------------------------------------

1. The standard reduction potential for the half-reaction

Sn4+ + 2e- Sn2+
is +0.15 V.
Consider data from the table of standard reduction potentials for common half-reactions, in your text.

For a galvanic cell under standard conditions, which of the following cathodic half reactions would produce, at the anode, a spontaneous oxidation of Sn to Sn2+ but not Sn2+ to Sn4+.

Sn2+ + 2e- Sn
Pb2+ + 2e- Pb
2H2O + 2e- H2 + 2OH-
PbSO4 + 2e- Pb + SO42-
Fe2+ + 2e- Fe
Fe3+ + 3e- Fe
 
yeah, something similar to that.
 
can someone please check what I'm doing wrong here... I'm still not getting the correct answer =(
 
if the Ecell = 0 (in equilibrium) is that still considered to be spontaneous?
 

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