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.

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, 20214 yr by studiot

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, 20214 yr by exchemist