[123456789]

In a beaker, if Mg is put into a solution of FeSO4, will the Mg displace Fe, or Hydrogen? The Eo value for Mg//H+ is higher than that of Mg//Fe2+, so technically H2 should be displaced?

Really confused-as I think experimentally Fe is displaced instead.

Also Mg does not react spontaneously with water (at rtp)...so it does not displace H2, but the Eo values state otherwise. I don't really get it...

[Borek]

Mg will displace hydrogen. Think about it this way: even if it would displace Fe, Fe is still reactive enough to displace hydrogen, so the overall process would be Mg displacing hydrogen.

And Mg reacts spontaneously with water, just the reaction is slow in pure water. Magnesium powder reacts much faster.