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 identify the presence of the -O-O- linkage in each compound. A peroxide bond is characterized by the presence of an oxygen-oxygen single bond where each oxygen atom has a formal charge of -1.

Let's analyze each compound step by step:

1. **Compound: O₂F₂ (Dioxygen difluoride)**
- Structure: The structure of O₂F₂ can be represented as F-O-O-F.
- Charge Distribution: In this compound, the fluorine atoms are more electronegative than oxygen. Therefore, the oxygen atoms will not have a -1 charge. Instead, the charge distribution leads to a situation where the oxygen atoms do not have the required -1 charge for a peroxide bond.
- Conclusion: **No peroxide bond.**

2. **Compound: H₂O₂ (Hydrogen peroxide)**
- Structure: The structure of H₂O₂ can be represented as H-O-O-H.
- Charge Distribution: In H₂O₂, the oxygen atoms are connected by a single bond (O-O). Each oxygen atom carries a formal charge of -1, satisfying the conditions for a peroxide bond.
- Conclusion: **Contains a peroxide bond.**

3. **Compound: H₂S₂O₈ (Disulfur octoxide)**
- Structure: The structure can be represented as HO-S(=O)-O-O-S(=O)-OH.
- Charge Distribution: In H₂S₂O₈, there is an -O-O- linkage. Each oxygen in this linkage can be assigned a formal charge of -1, indicating the presence of a peroxide bond.
- Conclusion: **Contains a peroxide bond.**

4. **Compound: CrO₅ (Chromium pentoxide)**
- Structure: The structure of CrO₅ includes two -O-O- linkages.
- Charge Distribution: In CrO₅, the oxygen atoms involved in the -O-O- bonds will also have a formal charge of -1. Therefore, this compound contains peroxide bonds.
- Conclusion: **Contains a peroxide bond.**

### Final Answer:
The compounds that contain peroxide bonds are:
- H₂O₂
- H₂S₂O₈
- CrO₅

### Summary:
- O₂F₂: No peroxide bond.
- H₂O₂: Contains a peroxide bond.
- H₂S₂O₈: Contains a peroxide bond.
- CrO₅: Contains a peroxide bond.