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Mod 3 q help (1 Viewer)

kkk579

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Why is the answer C and not D? Shouldnt we find the most and least reactive species? Ik that X ^ 2+ is least reactive ion and i thought that Y would be the most reactive metal since it is able to displace every ion in every reaction there is, whereas Z doesnt. ThanksScreenshot 2024-04-14 214405.png
 

wizzkids

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I think you are right. However, this is a weird question. To construct an electrochemical cell you would normally construct it from two half-cells. Each half-cell would contain a metal electrode in equilibrium with a solution of its own ions. The two half-cells would be connected by a salt-bridge.
This question is describing something very different - a metal electrode in contact with a solution of a different ion. There would be a spontaneous, non-equilibrium reaction and you could not experimentally measure the difference in electrode potential because the reaction would be occurring at thousands of tiny local cells where the oxidation and reduction reactions would be occurring in close proximity.
OK, so lets give the examiner the benefit of the doubt, and assume that they actually mean an electrochemical cell consisting of two metal electrodes.
From examination of column 2 of the table, we conclude that Pb, Y and Z all reduce X2+ ions. Therefore metal X has the highest reduction potential of all the metals under consideration, it is the least active metal (it could be silver, for example Eo=1.76 V). From consideration of column 4 we conclude that X, Pb and Z cannot reduce Y2+ to metallic Y. Therefore Y has the lowest reduction potential in the table (it could be Mg, Eo=-2.36 V), and the best answer is (D).
 

kkk579

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I think you are right. However, this is a weird question. To construct an electrochemical cell you would normally construct it from two half-cells. Each half-cell would contain a metal electrode in equilibrium with a solution of its own ions. The two half-cells would be connected by a salt-bridge.
This question is describing something very different - a metal electrode in contact with a solution of a different ion. There would be a spontaneous, non-equilibrium reaction and you could not experimentally measure the difference in electrode potential because the reaction would be occurring at thousands of tiny local cells where the oxidation and reduction reactions would be occurring in close proximity.
OK, so lets give the examiner the benefit of the doubt, and assume that they actually mean an electrochemical cell consisting of two metal electrodes.
From examination of column 2 of the table, we conclude that Pb, Y and Z all reduce X2+ ions. Therefore metal X has the highest reduction potential of all the metals under consideration, it is the least active metal (it could be silver, for example Eo=1.76 V). From consideration of column 4 we conclude that X, Pb and Z cannot reduce Y2+ to metallic Y. Therefore Y has the lowest reduction potential in the table (it could be Mg, Eo=-2.36 V), and the best answer is (D).
Thank you for the explanation!
 

Average Boreduser

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Only the uni libraries are big and even then theres still not enough seats πŸ˜” but they all way too far from me i cannot be bothered commuting that far
Im close to uni ones but I just cbf. my school has their library open until 9pm so i usually just get work done there when I need to
 

kkk579

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I mean its not just that tho like- I've heard uni students r getting rlly annoyed bc students doing their hscs are now studying in their libraries asw to the point where actual uni students there aren't able to find seating- so idk
Yeah thats fair tbh but like im sure a good portion of those uni students did the same during their hsc so they cant rlly be complaining 😭
 

Aeonium

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I mean its not just that tho like- I've heard uni students r getting rlly annoyed bc students doing their hscs are now studying in their libraries asw to the point where actual uni students there aren't able to find seating- so idk
they also get annoyed by random uni students doing very pasionate & non-studious activities in those libraries
 

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