REACTION BETWEEN HYDROCHLORIC ACID AND IRON
1. Composition of hydrochloric acid
Experiment 1: pH measurement
Observation: pH <7
Interpretation: Presence of H+ ions
Experiment 2: Silver nitrate test
Observation: White precipitate
Interpretation: Presence of Cl- ions
Reactants test. The pH meter to find the hydrogen ions because the solution is acidic and the silver nitrate to detect the chloride ion.
2. Reaction between iron and hydrochloric acid
Experiment 3: We have steel wool at the bottom of a tube. Pour a solution of hydrochloric acid.
- Iron disappears
- The solution turns green
- Release of flammable gas.
The gas observed is dihydrogen H2.
A chemical reaction has taken place in which iron is a reactant and hydrogen is a product.
3. Analysis of the solution after transformation
Exp.4: Add silver nitrate
Obs.: Always a white precipitate
Interp.: Cl- ions did not react.
Exp. 5: Add soda
Obs.: Green precipitate
Interp.: Fe2+ ions appeared
Exp. 6: We measure the pH
Obs.: The pH has increased
Interp.: H+ ions have disappeared
The balance sheet of the reaction between hydrochloric acid and iron is:
iron + hydrochloric acid → dihydrogen + iron II chloride solution
Hydrochloric acid: Hydrochloric acid is the salt of the hydronium ion, H3O+ and chloride. It is usually prepared by treating HCl with water.