[Damiano0707]

Immersing a bar of Fe in a water solution 0,100M PbCl2, 0,100M MnCl2, 0,100M MgCl2 and 0,00100M HCl, what happens?
A)Mn deposits on the bar
B)Mg deposits on the bar
C)Nothing happens
D)Pb deposits on the bar

Hi
I have some doubts about this problem. I know I have to apply Nernst equation but, in case of hydrogen, I have not the concentration of the oxidated state and the reduced one. Besides I have no temperature.

[Borek]

Start with just reactivity series, Nernst equation becomes important when potentials are very similar.

[Damiano0707]

 Thanks for the answer. But I can't understand what happens by just reactions

[Damiano0707]

I think I need to use potentials

[Borek]

I can't stop you from doing in the hard way, it is your choice if you want to waste time on things that can be done much faster and easier. Please remember reactivity series is based on the redox potentials, really no need to calculate exact potential to know whether Mg can deposit or not.

You can always assume room temperature (59.9 mV/n) and 1 atm for H₂.