Answer: The correct option is B.
Explanation:
The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction.
A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction.
The chemical species will undergo a reduction reaction if the value of standard reduction potential is more positive or less negative.
For the given half-reactions:
[tex]Mg^{2+}+2e^-\rightarrow Mg(s);E^o_{Mg^{2+}/Mg}=-2.37V[/tex]
[tex]Cu^{2+}(aq)+2e^-\rightarrow Cu(s);E^o_{Cu^{2+}/Cu}=+0.34V[/tex]
As the value of standard reduction potential of copper is positive thus, it will undergo a reduction reaction and magnesium will undergo an oxidation reaction.
The half-reaction follows:
Oxidation half-reaction: [tex]Mg(s)\rightarrow Mg^{2+}(aq)+2e^-[/tex]
Reduction half-reaction: [tex]Cu^{2+}(aq)+2e^-\rightarrow Cu(s)[/tex]
Overall cell-reaction: [tex]Mg(s)+Cu^{3+}(aq)\rightarrow Mg^{2+}(aq)+Cu(s)[/tex]
As it can be seen from the reaction that copper is forming as a pure metal in the product thus, it will be deposited and magnesium will be dissolved forming an aqueous solution.
Hence, the correct option is B.
