Question

which of these reactions if spontaneous?
(a) Fe^0 + Mg +2 --> Mg^0 +Fe+2
(b) Fe+2 + Mg ^0 --> Fe^0 + Mg +2

write the half cell equations for the spontaneous reaction.

which element is oxidized and which is reduced?

Answer 1

Look up the reduction potentials and calculate Ecell. If Ecell is positive the reaction is spontaneous.

The element oxidized is the element that lost electrons. Reduction is the gain of electrons.