Consider the following standard electrode potentials:
[tex]$\begin{array}{l}<
Mg^{2+}+2 e^{-} \longrightarrow Mg E^{\circ}=-2.37 v \\
Cg^{2+}+e^2 \longrightarrow Ce^{\circ}=+1.61 v
\end{array}$[/tex]
i. Write the cell notation for the voltaic cell
Answer (2)
Identify the anode and cathode based on the standard reduction potentials.
Write the half-cell reactions for the anode (oxidation) and cathode (reduction).
Construct the cell notation using the format: Anode | Anode Solution || Cathode Solution | Cathode.
The cell notation for the voltaic cell is M g ( s ) ∣ M g 2 + ( a q ) ∣∣ C e 2 + ( a q ) ∣ C e ( s ) .
Explanation
Understanding the Problem We are given the standard electrode potentials for Magnesium and Cerium. Our goal is to write the cell notation for the voltaic cell. The cell notation represents the electrochemical cell, indicating the anode (oxidation) on the left and the cathode (reduction) on the right, separated by a double vertical line representing the salt bridge.
Identifying Anode and Cathode First, we need to identify which metal will be oxidized (anode) and which will be reduced (cathode). This is determined by comparing their standard reduction potentials ( E ∘ ). The metal with the more negative E ∘ will be oxidized, and the metal with the more positive E ∘ will be reduced.
Determining Oxidation and Reduction Given: M g 2 + + 2 e − ⟶ M g E ∘ = − 2.37 V C e 2 + + 2 e − ⟶ C e E ∘ = + 1.61 V Magnesium has a more negative reduction potential (-2.37 V) compared to Cerium (+1.61 V). Therefore, Magnesium will be oxidized at the anode, and Cerium will be reduced at the cathode.
Writing Half-Cell Reactions Now, let's write the half-cell reactions: Anode (oxidation): M g ( s ) ⟶ M g 2 + ( a q ) + 2 e − Cathode (reduction): C e 2 + ( a q ) + 2 e − ⟶ C e ( s )
Writing the Cell Notation Finally, we can write the cell notation. The cell notation is written as: Anode | Anode Solution || Cathode Solution | Cathode In our case: M g ( s ) ∣ M g 2 + ( a q ) ∣∣ C e 2 + ( a q ) ∣ C e ( s )
Final Answer The cell notation for the voltaic cell is M g ( s ) ∣ M g 2 + ( a q ) ∣∣ C e 2 + ( a q ) ∣ C e ( s ) .
Examples
Voltaic cells, represented by cell notations, are used in batteries to power various devices. Understanding cell notations helps in designing and optimizing batteries for specific applications, such as electric vehicles or portable electronics. By knowing the electrode potentials, we can predict the voltage and overall performance of the battery, allowing for efficient energy storage and delivery.
The cell notation for the voltaic cell involving magnesium and cerium is M g ( s ) ∣ M g 2 + ( a q ) ∣∣ C e 2 + ( a q ) ∣ C e ( s ) . This notation shows that magnesium is oxidized at the anode while cerium is reduced at the cathode. Understanding this helps in predicting the behavior of voltaic cells in practical applications.
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