Which of the following set of compounds have peroxide bonds ?
1. `O_(2)F_(2) " "` 2. `H_(2)O_(2) " "` 3. `H_(2)S_(2)O_(8) " "` 4. `CrO_(5)`

Options

A. 1, 2, 3 and 4
B. 1, 2, 3 only
C. 2, 3, 4 only
D. 2, 4

Explanation

To determine which of the given compounds contain peroxide bonds, we need to analyze each compound's structure and the bonding of oxygen atoms. A peroxide bond is characterized by an oxygen-oxygen single bond (O-O) where each oxygen has a formal oxidation state of -1.

### Step-by-Step Solution:

1. **Analyze Compound 1: \( O_2F_2 \)**
- Structure: In \( O_2F_2 \), the two oxygen atoms are bonded to each other and to fluorine atoms.
- Oxidation States: The fluorine atoms are more electronegative, leading to the following oxidation states:
- Each fluorine (F) = -1
- Each oxygen (O) = +1
- Conclusion: There is no O-O bond with -1 oxidation states, so **\( O_2F_2 \) does not contain a peroxide bond.**

2. **Analyze Compound 2: \( H_2O_2 \) (Hydrogen Peroxide)**
- Structure: \( H_2O_2 \) has the formula where two oxygen atoms are bonded to each other (O-O) and to hydrogen atoms.
- Oxidation States:
- Each hydrogen (H) = +1
- Each oxygen (O) = -1
- Conclusion: The presence of the O-O bond with both oxygens having -1 oxidation states confirms that **\( H_2O_2 \) contains a peroxide bond.**

3. **Analyze Compound 3: \( H_2S_2O_8 \)**
- Structure: This compound can be represented as \( H_2O_2S_2 \) with a central S-S bond and O-O bond.
- Oxidation States:
- Each sulfur (S) = +6
- Each oxygen in the O-O bond = -1
- Conclusion: The O-O bond with -1 oxidation states indicates that **\( H_2S_2O_8 \) contains a peroxide bond.**

4. **Analyze Compound 4: \( CrO_5 \)**
- Structure: In \( CrO_5 \), chromium is bonded to five oxygen atoms, one of which is part of a peroxide group.
- Oxidation States:
- Each oxygen in the O-O bond = -1
- The remaining oxygens will have a higher oxidation state to balance the charge.
- Conclusion: The presence of the O-O bond with -1 oxidation states confirms that **\( CrO_5 \) contains a peroxide bond.**

### Final Conclusion:
The compounds that contain peroxide bonds are:
- \( H_2O_2 \) (2)
- \( H_2S_2O_8 \) (3)
- \( CrO_5 \) (4)

Thus, the correct answer is **2, 3, and 4**.