Consider the following table of standard reduction potentials.
`{:("Reaction",E^@(V)),(A^(3+)+2e^(-) rarrA^+,1.36),(B^(2+)+2e^(-)rarrB,0.72),(C^(2+)+2e^(-)rarrC,-0.28),(D^(+)+e^(-)rarrD,-1.42):}`
Which substance can be oxidised by `B^(2+)` ?

Answer

To determine which substance can be oxidized by \( B^{2+} \), we will analyze the standard reduction potentials provided in the table. The key concept here is that a species with a higher reduction potential can oxidize a species with a lower reduction potential.

### Step-by-Step Solution:

1. **Identify the Standard Reduction Potentials:**
- From the table, we have the following standard reduction potentials:
- \( E^\circ(A^{3+} + 2e^- \rightarrow A) = 1.36 \, V \)
- \( E^\circ(B^{2+} + 2e^- \rightarrow B) = 0.72 \, V \)
- \( E^\circ(C^{2+} + 2e^- \rightarrow C) = -0.28 \, V \)
- \( E^\circ(D^{+} + e^- \rightarrow D) = -1.42 \, V \)

2. **Determine the Reduction Potential of \( B^{2+} \):**
- The reduction potential of \( B^{2+} \) is \( 0.72 \, V \).

3. **Compare with Other Species:**
- We need to find substances that have a higher reduction potential than \( B^{2+} \):
- \( A^{3+} \) has a reduction potential of \( 1.36 \, V \) (higher than \( 0.72 \, V \)).
- \( C^{2+} \) has a reduction potential of \( -0.28 \, V \) (lower than \( 0.72 \, V \)).
- \( D^{+} \) has a reduction potential of \( -1.42 \, V \) (lower than \( 0.72 \, V \)).

4. **Identify the Oxidizing Agent:**
- Since \( A^{3+} \) has a higher reduction potential than \( B^{2+} \), it can oxidize \( B^{2+} \).
- Therefore, \( A^{3+} \) can oxidize \( B^{2+} \).

5. **Conclusion:**
- The substance that can be oxidized by \( B^{2+} \) is \( A^{3+} \).

### Final Answer:
\( A^{3+} \) can oxidize \( B^{2+} \).

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