Which equation represents the oxidation half-reaction for this redox reaction?
Mg + CuSO4 → MgSO4 + Cu

A.
Mg → Mg
B.
Mg → Mg + O4
C.
Mg → Mg + 2e−
D.
Mg → Mg + 3e−

C.   Mg → Mg²⁺ + 2e−

Explanation:

The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining or losing the electrons and oxidation state of elements are changed.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

Consider the following reactions.

Mg + CuSO₄      →    MgSO₄  + Cu

Mg atom lose two electron and gets oxidized.

Mg → Mg²⁺ + 2e−

These two electrons are accepted by Cu and gets reduced.

CuSO₄       →      Cu²⁺ + SO₄²⁻

Cu²⁺ + 2e⁻   →  Cu

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l