Question

Why do voltaic cells with magnesium as the annode have such high percent differences?

Redox table predicts high potentials, but the experiment recorded much lower potentials. This was specifically for cells with magnesium as an annode.

Answer 1

see below

Explanation:

You don't explain your experiment but the couple `Mg`/`Mg^(2+)` cannot be used as anode in water solutions because it reacts with water, furthermore in place of `Mg`/`Mg^(2+)` E=-2,36 V react `H^+`/`H_2` with E=0 V whose potential changes with pH according with the relation: `E=` 0-0,0592 pH (V)