Are any of the bellow chemical changes reversible? If yes, then how?

Mixture of Lear Nitrate and Potassium Iodide
Mixture of Copper Sulphate Solution and Iron
Mixture of Copper Sulphate Solution and Sodium Carbonate
Mixture of Dilute Hydrochloric Acid and Magnesium
Mixture of Dilute Hydrochloric Acid and Calcium Carbonate
Mixture of Dilute Hydrogen Peroxide and Maganese Dioxide

What do you not know that keeps you from answering this question?

I know that all of this are chemical changes and mostly all chemical changes are non reversible. However, there are some that are reversible. I'm just not sure if any of this ones are reversible or no.

To determine whether any of the chemical changes in the given mixtures are reversible, we need to understand the nature of the reactions and the products formed.

1. Mixture of Lead Nitrate and Potassium Iodide:
The reaction between lead nitrate and potassium iodide forms a precipitate of lead iodide and potassium nitrate. This reaction is not reversible as the formation of a precipitate indicates a chemical change that cannot be easily reversed.

2. Mixture of Copper Sulphate Solution and Iron:
The reaction between copper sulphate solution and iron leads to the displacement of copper by iron. Copper gets deposited on iron while iron ions are released in the solution. This reaction is reversible to some extent. The copper coating can be removed from iron by using dilute acids like hydrochloric acid.

3. Mixture of Copper Sulphate Solution and Sodium Carbonate:
When copper sulphate solution reacts with sodium carbonate, it forms a precipitate of copper carbonate and sodium sulphate. This reaction is not reversible as a precipitate is formed, indicating a chemical change that cannot be easily reversed.

4. Mixture of Dilute Hydrochloric Acid and Magnesium:
The reaction between dilute hydrochloric acid and magnesium produces magnesium chloride and hydrogen gas. This reaction is not reversible as hydrogen gas is evolved, representing a chemical change that cannot be easily reversed.

5. Mixture of Dilute Hydrochloric Acid and Calcium Carbonate:
When dilute hydrochloric acid reacts with calcium carbonate, it produces calcium chloride, carbon dioxide gas, and water. This reaction is not reversible as carbon dioxide gas is generated, suggesting a chemical change that cannot be easily reversed.

6. Mixture of Dilute Hydrogen Peroxide and Manganese Dioxide:
The reaction between dilute hydrogen peroxide and manganese dioxide leads to the formation of water and oxygen gas. This reaction is not reversible as oxygen gas is released, indicating a chemical change that cannot be easily reversed.

In summary, out of the given mixtures, the only reaction that is partially reversible is the mixture of copper sulphate solution and iron.