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Postby Ami_Pant_4G » Wed Mar 04, 2020 6:55 pm

The “aluminum–air fuel cell” is used as a reserve battery in remote locations. In this cell, aluminum reacts with the oxygen in air in basic solution. (a) Write the oxidation and reduction halfreactions for this cell. (b) Calculate the standard cell potential

For part A I figured out the half reactions would be the half reaction of Al and the half reaction of O2 (the one that has OH- in the reaction), but I don't know which one would be the cathode and whice would be the anode? thanks in advance.

Connie Chen 1E
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Re: 6.73

Postby Connie Chen 1E » Fri Mar 06, 2020 10:29 am

If you look at the standard cell potentials for the half reactions, you'll see that Al3+ + 3e- --> Al has a Eo of -1.66 V and O2 + 2 H2O + 4 e- --> 4 OH- has a Eo of 0.40 V. So you know that Al has to be the anode and O2 has to be the cathode.

Emma Popescu 1L
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Re: 6.73

Postby Emma Popescu 1L » Sat Mar 07, 2020 10:13 pm

The half reaction with the highest standard potential is the cathode. E cell needs to be positive in order for the reaction to be spontaneous.

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