Potassium chloride → potassium → potassium hydroxide → potassium sulfate → potassium chloride.

In this task you will need to compose chemical reaction equations for the following chain of compounds.
KCl -> K -> KOH -> K2SO4 -> KCl.
1. Decomposition reaction.
2KCl = 2K + Cl2 ↑.
Potassium chloride decomposes into potassium and chlorine.
2. Substitution reaction.
2K + 2H2O = 2KOH + H2.
When potassium reacts with water, the result is potassium hydroxide and hydrogen.
3. Reaction of exchange.
KOH + H2SO4 = 2K2SO4 + 2H2O.
Potassium hydroxide with sulfuric acid results in potassium sulfate and water.
4. Exchange reaction.
K2SO4 + BaCl2 = BaSO4 ↓ + 2KCl.
When potassium sulfate and barium chloride react, the result is barium sulfate and potassium chloride.