Assuming the schematics below represent galvanic cells as written, identify the half-cell reactions occurring in each. (a) \(\operatorname{Mg}(s)\left|\operatorname{Mg}^{2+}(a q) \| \mathrm{Cu}^{2+}(a q)\right| \mathrm{Cu}(s)\) (b) \(\mathrm{Ni}(s)\left|\mathrm{Ni}^{2+}(a q) \| \mathrm{Ag}^{+}(a q)\right| \mathrm{Ag}(s)\)

Anode oxidation reactions are a fundamental aspect of electrochemistry – the study of how chemical energy is converted to electrical energy through redox reactions. Anodes are the electrodes where oxidation takes place in a galvanic cell.

During an oxidation reaction, an element loses electrons. This is typically represented by a chemical equation showing the starting material and the products after electron loss. In our example with magnesium and nickel cells:

• In cell (a): \[\begin{equation}\operatorname{Mg}(s) \rightarrow \operatorname{Mg}^{2+}(aq) + 2e^- \right)\br>\end{equation}\]Magnesium metal (Mg) loses two electrons to become magnesium ion (\(\operatorname{Mg}^{2+}\)).
• In cell (b): \[\begin{equation}\mathrm{Ni}(s) \rightarrow \mathrm{Ni}^{2+}(aq) + 2e^- \right)\right)\right)\br>\end{equation}\]Nickel (\(\mathrm{Ni}\)) undergoes oxidation, shedding two electrons and forming nickel ions (\(\mathrm{Ni}^{2+}\)).

It's important to note that the electrons produced at the anode flow through the external circuit towards the cathode, generating electric current.

Conversely to the anode, the cathode is where reduction reactions occur in a galvanic cell. Reduction is the gain of electrons by a substance, which can be seen in the half-cell reactions at the cathode.

In our exercise:

• For cell (a), copper ions (\(\mathrm{Cu}^{2+}\)) in solution accept two electrons to form solid copper (\(\mathrm{Cu}(s)\)):\[\begin{equation}\mathrm{Cu}^{2+}(aq) + 2e^- \rightarrow \mathrm{Cu}(s)\right)\right)\end{equation}\]
• For cell (b), silver ions (\(\mathrm{Ag}^{+}\)) receive an electron to become solid silver (\(\mathrm{Ag}(s)\)):\[\begin{equation}\mathrm{Ag}^{+}(aq) + e^- \rightarrow \mathrm{Ag}(s)\right)\right)\end{equation}\]

Reduction at the cathode complements oxidation at the anode, and together, they allow the electrochemical cell to function by moving electrons from the anode to the cathode, facilitating a flow of electrical current through the circuit.

Half-cell reactions are the individual oxidation and reduction reactions that occur in separate compartments of a galvanic cell. Electrochemical cells consist of two half-cells, each with its own electrode and ionic solution.

The separation of the cell into half-cells is crucial for the independent investigation of the oxidation and reduction processes that occur during the operation of the cell.

Every half-cell has its own characteristic potential, and the difference between the potentials of the anode and cathode half-cells determines the cell potential. For instance:

• In our galvanic cell (a), the magnesium anode half-cell reaction is:\[\begin{equation}\operatorname{Mg}(s) \rightarrow \operatorname{Mg}^{2+}(aq) + 2e^-\right)\end{equation}\]
• The copper cathode half-cell is as follows:\[\begin{equation}\mathrm{Cu}^{2+}(aq) + 2e^- \rightarrow \mathrm{Cu}(s)\right)\end{equation}\]

Analyzing half-cell reactions is key to understanding how galvanic cells work and what drives the flow of electrons that provide us with electrical energy.

Electrochemistry delves into chemical processes that involve the movement of electrons, particularly those that convert chemical energy into electrical energy and vice versa.

This field of science encompasses a wide range of applications, from batteries to electrolysis to fuel cells. At the heart of these applications are redox reactions, which occur at the electrodes in an electrochemical cell. Galvanic cells, also known as voltaic cells, are a type of electrochemical cell that generates electrical energy from spontaneous chemical reactions.

Understanding the principles of electrochemistry is essential for students and professionals in various fields, including energy storage, corrosion prevention, and environmental chemistry. It offers an insight into the core of how different materials interact when in contact with each other and an electrical current, providing a bridge between physical science and practical technology.