possible mistake: GS FL #1

[epsilonprodigy]

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I think I found a mistake in the GS-1 full length.




49) Which of the following is the strongest reducing agent?
Electrochemical reactionEo value (V)MnO2 + 4H+ + 2e- ↔ Mn2+ + 2H2O+1.23Fe3+ + e- ↔ Fe2+ +0.771 N2 + 5H+ + 4e- ↔ N2H5+-0.230Cr3+ + e- ↔ Cr2+ -0.410

Wouldn't the strongest reducing agent have the HIGHEST oxidation potential and the MOST NEGATIVE (lowest) reduction potential?

 

[Mcat35]

Electrochemical reaction Eo value (V)
MnO2 + 4H+ + 2e- ↔ Mn2+ + 2H2O +1.23
Fe3+ + e- ↔ Fe2+ +0.771
N2 + 5H+ + 4e- ↔ N2H5+ -0.230
Cr3+ + e- ↔ Cr2+ -0.410


thats what you are trying to copy paste right? I took this test as well..

Anyway...

your assumption is right however we are given the E0 which is the reductive potential. (higher reductive potential, the easier the forward reaction can proceed (easier to get reduced)

Its asking for reducting potential so if you look at the last equation you see that Cr3+ has a negative reduction potential so it is very hard to reduce Cr3+. At least harder than the other ones on that list.

However because it is hard to reduce Cr3+ it is very ez to oxidize the counterpart cr2+ therefore Cr2+ is the right answer as it is the easily oxidized therefore it is the strongest reducing agent.


Lesson here smaller reduction potential / easier the reverse reaction of being oxidized.

 

[GreenRabbit]

What you said is exactly what OP said.

 

[Mcat35]

What you said is exactly what OP said.

if you can see the table better you have an better idea, but the copy paste thing doesn't work very well.

he was in essence right, but I was just trying to show him how that was not a GS mistake, that the answer is correct.. unless he is basing it off the GS explanation and not the answer... I didn't read the GS explanation since I knew how to do this type of problems.