To identify if each reaction is an oxidation or a reduction, it is important to understand the fundamental concepts:
1. Oxidation is the loss of electrons.
2. Reduction is the gain of electrons.
Given this understanding, let's evaluate each reaction:
1. [tex]$Be^{2+}(aq) + 2e^{-} \rightarrow Be(s)$[/tex]
- Here, the beryllium ion [tex]\(Be^{2+}\)[/tex] is gaining 2 electrons to become neutral beryllium metal [tex]\(Be\)[/tex]. Since it is gaining electrons, this reaction is a reduction.
2. [tex]$Cd(s) \rightarrow Cd^{2+}(aq) + 2e^{-}$[/tex]
- In this reaction, cadmium metal [tex]\(Cd\)[/tex] is losing 2 electrons to form a cadmium ion [tex]\(Cd^{2+}\)[/tex]. Since it is losing electrons, this reaction is an oxidation.
3. [tex]$Co^{3+}(aq) + e^{-} \rightarrow Co^{2+}(aq)$[/tex]
- Here, the cobalt ion [tex]\(Co^{3+}\)[/tex] is gaining 1 electron to become a cobalt ion [tex]\(Co^{2+}\)[/tex]. Since it is gaining electrons, this reaction is a reduction.
4. [tex]$Al(s) \rightarrow Al^{3+}(aq) + 3e^{-}$[/tex]
- In this reaction, aluminum metal [tex]\(Al\)[/tex] is losing 3 electrons to form an aluminum ion [tex]\(Al^{3+}\)[/tex]. Since it is losing electrons, this reaction is an oxidation.
Now, let's categorize these reactions:
### Reduction:
- [tex]$Be^{2+}(aq) + 2e^{-} \rightarrow Be(s)$[/tex]
- [tex]$Co^{3+}(aq) + e^{-} \rightarrow Co^{2+}(aq)$[/tex]
### Oxidation:
- [tex]$Cd(s) \rightarrow Cd^{2+}(aq) + 2e^{-}$[/tex]
- [tex]$Al(s) \rightarrow Al^{3+}(aq) + 3e^{-}$[/tex]
In conclusion, the reactions have been identified as follows:
Reduction Reactions:
- [tex]$Be^{2+}(aq) + 2e^{-} \rightarrow Be(s)$[/tex]
- [tex]$Co^{3+}(aq) + e^{-} \rightarrow Co^{2+}(aq)$[/tex]
Oxidation Reactions:
- [tex]$Cd(s) \rightarrow Cd^{2+}(aq) + 2e^{-}$[/tex]
- [tex]$Al(s) \rightarrow Al^{3+}(aq) + 3e^{-}$[/tex]
