starchaser137 Posted May 6, 2021 Share Posted May 6, 2021 I have this salt water car kit in which the power source is 3 components - a magnesium sheet, a "non-woven fabric" and an "air cathode". When I stack these with the fabric in the centre after soaking the fabric with salt water, it generates a potential difference in the whole thing. Can anyone please explain how this happens? I really need a reaction for this and a description would be really nice. Link to comment Share on other sites More sharing options...
studiot Posted May 6, 2021 Share Posted May 6, 2021 (edited) 18 minutes ago, starchaser137 said: a description would be really nice. A picture of your apparatus perhaps ? Here is a Royal Society of Chemistry diagram of such a cell, including the requested reactions. Is your air cathode porous carbon of some sort ? The reaction requires oxygen from the air to permeate through it. Edited May 6, 2021 by studiot Link to comment Share on other sites More sharing options...
exchemist Posted May 6, 2021 Share Posted May 6, 2021 (edited) 19 minutes ago, starchaser137 said: I have this salt water car kit in which the power source is 3 components - a magnesium sheet, a "non-woven fabric" and an "air cathode". When I stack these with the fabric in the centre after soaking the fabric with salt water, it generates a potential difference in the whole thing. Can anyone please explain how this happens? I really need a reaction for this and a description would be really nice. The overall reactions appears to be Mg + H₂O + 1/2 O₂ -> Mg(OH)₂. There is a description of how it works here: https://pubs.rsc.org/en/content/articlehtml/2014/mh/c3mh00059a The clever bit, it seems to me, is the "air cathode". This seems to be a multi-layer structure, incorporating a conductive layer (obviously) bonded to a catalyst layer, which seems to involve silver as the material that encourages oxygen to react. I have not read this in detail, but it looks as if optimising this part of it is an active area of research. Edited May 6, 2021 by exchemist Link to comment Share on other sites More sharing options...
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