To identify the species oxidized and reduced in the given electron-transfer reaction, we need to analyze the changes in the oxidation states of the elements involved in the reaction. Here's the reaction:
[tex]\[ \text{3 Mg (s) + 2 Al}^{3+} \text{(aq)} \rightarrow \text{3 Mg}^{2+} \text{(aq) + 2 Al (s)} \][/tex]
### Step 1: Identify the Oxidation States
First, let's identify the initial and final oxidation states of the elements involved:
1. Magnesium (Mg):
- Initially: The oxidation state of Mg in its elemental form (solid magnesium) is 0.
- Finally: The oxidation state of Mg in the ion form [tex]\(\text{Mg}^{2+}\)[/tex] is +2.
2. Aluminum (Al):
- Initially: The oxidation state of Al in the ion form [tex]\(\text{Al}^{3+}\)[/tex] is +3.
- Finally: The oxidation state of Al in its elemental form (solid aluminum) is 0.
### Step 2: Determine the Changes in Oxidation States
Now, let's see how the oxidation states change during the reaction:
- Magnesium (Mg) changes from 0 to +2.
- This means magnesium loses electrons, and thus, it undergoes oxidation.
- [tex]\(\text{Mg} \rightarrow \text{Mg}^{2+} + 2 e^-\)[/tex]
- Aluminum (Al) changes from +3 to 0.
- This means aluminum gains electrons, and thus, it undergoes reduction.
- [tex]\(\text{Al}^{3+} + 3 e^- \rightarrow \text{Al}\)[/tex]
### Step 3: Identify the Species Oxidized and Reduced
- Species oxidized: The species that loses electrons in the reaction is oxidized. Here, magnesium (Mg) is oxidized because it goes from an oxidation state of 0 to +2.
- Species reduced: The species that gains electrons in the reaction is reduced. Here, aluminum ion ([tex]\(\text{Al}^{3+}\)[/tex]) is reduced because it goes from an oxidation state of +3 to 0.
Species oxidized: Mg
Species reduced: Al
### Step 4: Direction of Electron Transfer
As the reaction proceeds, electrons are transferred:
- From the magnesium ([tex]\(\text{Mg}\)[/tex]), which is being oxidized and losing electrons.
- To the aluminium ion ([tex]\(\text{Al}^{3+}\)[/tex]), which is being reduced and gaining electrons.
So, electrons are transferred from [tex]\(\text{Mg}\)[/tex] to [tex]\(\text{Al}^{3+}\)[/tex].
### Final Answer:
Species oxidized: Mg
Species reduced: Al
As the reaction proceeds, electrons are transferred from [tex]\(\text{Mg}\)[/tex] to [tex]\(\text{Al}^{3+}\)[/tex].
