Fluorine is very reactive and attacks all metals but still a copper vessel is used in the preparation of fluorine gas. Why?

Explanation

**Step-by-Step Solution:**

1. **Understanding Fluorine's Reactivity**: Fluorine is known to be one of the most reactive elements. It readily reacts with almost all metals, forming metal fluorides.

2. **Use of Copper Vessels**: Despite its reactivity, copper vessels are used for the preparation of fluorine gas. This seems contradictory at first because one would expect fluorine to corrode the copper.

3. **Reaction of Fluorine with Copper**: When fluorine gas comes into contact with copper, a chemical reaction occurs. The reaction produces copper fluoride (CuF2):
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