Answer:
Oxidation state for Mg(s) is 0
Explanation:
This is redox reaction, where one element is oxidized and another is reduced.
H from water is being reduced while the Mg which is in ground state is oxidized.
When the element is reduced, the oxidation state is decreased:
2H⁺ + 2e⁻ ⇄ H₂
When the element is oxidized, the oxidation state is increased
Mg ⇄ Mg²⁺ + 2e⁻
As Mg(s) in the product side, is at ground state, the oxidation state is 0.
Any element in ground state has 0, as oxidation state.
