Which of the folowing undergoes disproportionation?

Options

A. `Ba^(2+)`
B. `Ba^(o+)`
C. `BaH_(2)`
D. `BaSO_(4)`

Explanation

To determine which of the following undergoes disproportionation, we first need to understand what a disproportionation reaction is. A disproportionation reaction is a type of redox reaction in which a single species is both oxidized and reduced, resulting in the formation of two different products from the same reactant.

### Step-by-Step Solution:

1. **Identify the Species**: We need to analyze the given options to identify which species can undergo disproportionation. The options are likely to include various oxidation states of alkaline earth metals.

2. **Understanding Oxidation States**: For a species to undergo disproportionation, it must have at least three different oxidation states. This allows one part of the molecule to be oxidized (increase in oxidation state) and another part to be reduced (decrease in oxidation state).

3. **Analyzing Each Option**:
- **Option A: Ba²⁺**: Barium in the +2 oxidation state is stable and does not have a higher oxidation state to oxidize to. Therefore, it cannot undergo disproportionation.
- **Option B: Ba⁺**: Barium in the +1 oxidation state can potentially disproportionate to form Ba (0 oxidation state) and Ba²⁺. This means Ba⁺ can be both oxidized and reduced, indicating that it can undergo disproportionation.
- **Option C and D**: If these options also represent barium in the +2 oxidation state (like Ba²⁺), they would similarly not undergo disproportionation for the same reasons as option A.

4. **Conclusion**: Based on the analysis, the species that can undergo disproportionation is **Ba⁺** (Option B).

### Final Answer:
**The species that undergoes disproportionation is Ba⁺.**