What is the shorthand notation that represents the following galvanic cell reaction? Mg(s) + Cu(NO3)2(aq) → Mg?

Cu(s) | Cu2+(aq) | | Mg 2+(aq) | Mg(s)

Mg(s) | Mg 2+(aq) | | Cu2+(aq) | Cu(s)

Cu(s) | Cu(NO3)2(aq) | | Mg(NO3)2(aq) | Mg(s)

1 Answer

• The cell reaction is: Mg(s) + Cu+2(aq) ====> Mg+2(aq) + Cu(s)

  The cell anode and cathode (half-cells) are separated by two bars or slashes, which represent a salt bridge.

  The anode is placed on the left and the cathode on the right.

  Individual solid, liquid, or aqueous phases within each half-cell are written separated by a single bar.

  Concentrations of dissolved species can be written in the parentheses after the phase notation (s, l, g, or aq).

  The anode is the electrode where oxidation(loss of electrons) occurs: Mg =⇒ Mg+2 + 2e-

   reduction occurs at the cathode:  Cu+2  +  2e-  ===> Cu

  Thus, the correct answer is: Mg(s) | Mg 2+(aq) | | Cu2+(aq) | Cu(s)