Which of the following is are redox reaction(s) ?

Options

A. `BaO_(2)+H_(2)SO_(4)toBaSO_(4)+H_(2)O_(2)`
B. `2BaO+O_(2)to2BaO_(2)`
C. `2kClO_(3)to2kCl+3O_(2)`
D. `SO_(2)+2H_(2)Sto2H_(2)O+3S`

Explanation

To determine which of the given reactions are redox reactions, we need to analyze the oxidation states of the elements involved in each reaction. A redox reaction involves the transfer of electrons, where one species is oxidized (loses electrons) and another is reduced (gains electrons).

### Step-by-Step Solution:

1. **Identify the Reactions**: List the reactions provided in the question. For this example, we will analyze the reaction given in the transcript:
\[ \text{BaO}_2 + \text{H}_2\text{O}_4 \rightarrow \text{BaSO}_4 + \text{H}_2\text{O}_2 \]

2. **Assign Oxidation States**:
- For **BaO₂**:
- Ba = +2 (alkaline earth metal)
- O = -1 (in peroxides)
- For **H₂O₄ (H₂SO₄)**:
- H = +1
- O = -2
- S = +6 (since there are 4 O atoms contributing -8, to balance, S must be +6)
- For **BaSO₄**:
- Ba = +2
- S = +6
- O = -2
- For **H₂O₂**:
- H = +1
- O = -1

3. **Calculate Changes in Oxidation States**:
- In **BaO₂**, O changes from -1 to 0 in H₂O₂ (oxidation).
- In **H₂O₄**, S remains +6, but O changes from -2 to -2 in BaSO₄ (no change).
- In **H₂O₂**, O changes from -1 to 0 (oxidation).

4. **Determine if Redox Occurs**:
- Since there is a change in oxidation states (O is oxidized from -1 to 0), this indicates that oxidation is occurring.
- Therefore, BaO₂ is oxidized, and H₂O₂ is reduced (as it gains electrons).

5. **Conclusion**: The reaction is a redox reaction because there is both oxidation and reduction taking place.