Among the halide ions, ............. is the most powerful reducing agent.

Explanation

To determine which halide ion is the most powerful reducing agent among fluoride, chloride, bromide, and iodide, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Oxidation and Reduction**:
- Oxidation is defined as the loss of electrons.
- Reduction is defined as the gain of electrons.
- A reducing agent is a substance that donates electrons to another substance and gets oxidized in the process.
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