Explaining Electrolysis Results

[Uber-Dan]

Hello all, 

I’m not sure whether to put this in the physics or chemistry section, so here goes. I have been conducting an experiment consisting of running 6 volts of electricity through an electrolytic cell made up of two steel electrodes submerged in salt water, and then measuring the amperage generated. I would then change the concentration of salt in the solution and test it again. So the first test was with 0.5g/100ml, then 1g/100ml etc. My question resolves interpretating the results. The averages of the results were as follows:

0.5g/100ml = 0.147A : Uncertainty % = 3.409%

1g/100ml = 0.237A : Uncertainty % = 4.225%

1.5g/100ml = 0.290A : Uncertainty % = 1.724%

2g/100ml = 0.333A : Uncertainty % = 1.500%

2.5g/100ml = 0.363A : Uncertainty % = 4.128%

The experiment was conducted in a test tube with fairly close electrodes. My question is, why do the results create an exponential curve and not form a linear relationship between the concentration of solute and the amperage generated? I can only assume it is something to do with the voltage not being that high, or that some other chemical reaction is taking place more often when the ion concentration has gone up. I’m really not sure, so what are your thoughts?

Regards, Dan

[chenbeier]

Check Kohlrausch law 1 and 2.

Conductivity can not be measured by using direct current. You need high frequency AC device  about 1000 Hz and a wheastonbridge measurement.

Depending on the electrolyte you get electrolysis effects on the electrodes.

 

 

Edited August 7, 2019 by chenbeier