The reaction between chlorine (Cl₂) and potassium astatide (KAt) is a single displacement reaction, where chlorine, being more reactive than astatine, displaces astatine from the compound. This results in the formation of potassium chloride (KCl) and elemental astatine (At₂).

Reaction:

Cl₂ (g) + 2KAt (s) → 2KCl (s) + At₂ (s)

Explanation:

* Chlorine (Cl₂) is a halogen, and it exists as a diatomic molecule in its elemental state.

* Potassium astatide (KAt) is a salt where potassium (K) is bonded to astatine (At).

* Chlorine is more reactive than astatine in the halogen reactivity series.

* When chlorine reacts with potassium astatide, it displaces astatine from the compound.

* The result is the formation of potassium chloride (KCl), another salt, and elemental astatine (At₂), which is a solid at room temperature.

Important Note:

* This reaction is theoretical because astatine is a highly radioactive element, and its compounds are very unstable and difficult to synthesize.

* The exact conditions and products of this reaction are not well-studied.