Select the example of desproportionaton reaction

Options

A. `BaCl_(2)+H_(2)SO_(4)rarrBaSO_(4)+2HCl`
B. `NH_(4)NO_(3)rarrN_(2)O+2H_(2)O`
C. `4H_(3)PO_(3)rarrPH_(3)+3H_(3)PO_(4)`
D. `AgCl+2NH_(3)rarrAg(NH_(3))_(2)Cl`

Answer

To solve the question of selecting an example of a disproportionation reaction, we need to understand what a disproportionation reaction is. A disproportionation reaction is a type of redox reaction where a single substance is both oxidized and reduced, resulting in the formation of two different products.

### Step-by-Step Solution:

1. **Understand the Definition**:
- A disproportionation reaction involves a single compound undergoing both oxidation and reduction, leading to the formation of two different products.

2. **Analyze Each Reaction**:
- **Reaction A**: \( \text{BaCl}_2 + \text{H}_2\text{SO}_4 \rightarrow \text{BaSO}_4 + 2\text{HCl} \)
- Oxidation states: Ba = +2, Cl = -1, S = +6 (no change in oxidation states)
- Conclusion: No oxidation or reduction occurs. **Not a disproportionation reaction.**

- **Reaction B**: \( 2\text{H}_2\text{O} \)
- Oxidation states: H = +1, O = -2 (no change in oxidation states)
- Conclusion: No oxidation or reduction occurs. **Not a disproportionation reaction.**

- **Reaction C**: \( 4\text{H}_3\text{PO}_3 \rightarrow \text{PH}_3 + 3\text{H}_3\text{PO}_4 \)
- Oxidation states:
- In \( \text{H}_3\text{PO}_3 \), P = +3
- In \( \text{PH}_3 \), P = -3
- In \( \text{H}_3\text{PO}_4 \), P = +5
- Here, phosphorus is oxidized from +3 to +5 and reduced from +3 to -3.
- Conclusion: This is a disproportionation reaction.

- **Reaction D**: \( \text{AgCl} + 2\text{NH}_3 \rightarrow \text{Ag(NH}_3\text{)}_2\text{Cl} \)
- Oxidation states: Ag = +1, Cl = -1, N = -3 (no change in oxidation states)
- Conclusion: No oxidation or reduction occurs. **Not a disproportionation reaction.**

3. **Final Conclusion**:
- The only reaction that shows both oxidation and reduction of the same element (phosphorus) is **Reaction C**: \( 4\text{H}_3\text{PO}_3 \rightarrow \text{PH}_3 + 3\text{H}_3\text{PO}_4 \). Therefore, this is the example of a disproportionation reaction.