Which of these substances is a good reducing agent

Options

A. NaOCl
B. HI
C. `FeCl_3`
D. KBr

Explanation

To determine which of the given substances is a good reducing agent, we need to understand the characteristics of reducing agents. A reducing agent is a substance that can donate electrons to another substance, thereby reducing it while itself being oxidized.

### Step-by-Step Solution:

1. **Understand the Definition of Reducing Agents**:
- Reducing agents are substances that can lose electrons easily. They often contain elements that can be oxidized, such as metals or compounds that can release hydrogen.

2. **Identify the Given Substances**:
- In this case, we are specifically looking at Hydrogen Iodide (HI) as a potential reducing agent.

3. **Analyze Hydrogen Iodide (HI)**:
- HI consists of hydrogen and iodine. The key point here is that hydrogen can easily be released from HI.
- When HI dissociates, it can release hydrogen ions (H⁺), which can then participate in reduction reactions.

4. **Evaluate the Reducing Ability**:
- Since HI can release hydrogen easily, it can effectively reduce other compounds. This means HI can donate electrons to other substances, thus acting as a reducing agent.

5. **Conclusion**:
- Based on the analysis, HI is indeed a good reducing agent because it can easily provide hydrogen that reduces other compounds.

### Final Answer:
- Hydrogen Iodide (HI) is a good reducing agent.