In a reaction sequence, one or more products are generally formed. Let us see how the reaction of HCl and Fe2O3 occurs.
Hydrochloric acid can be found in both liquid and gaseous (hydrogen chloride) forms. Iron(III) Oxide(Fe2O3) is naturally found as Haematite ore in rocks and can be prepared from even normal oxidation of Iron. These crystals have various polymorphs and are used in the production of Iron and such alloys.
In this article, we will observe the reaction properties and products of the acid and the metal oxide.
What is the product of HCl and Fe2O3?
HCl and Fe2O3 react to form Ferric Chloride and water respectively. The reaction equation is:
- Fe2O3 + 6HCl = 2FeCl3 + 3H2O
What type of reaction is HCl + Fe2O3?
The reaction of HCl with Fe2O3 is a neutralisation reaction as the amphoteric Iron oxide reacts with the acid to give salt and water.
How to balance HCl and Fe2O3?
Following are the steps to equate the above reaction scheme:
- Step 1: Put the general chemical equation:
- Fe2O3 + HCl = FeCl3 + H2O
- Step 2: As both sides should be equal in atoms, keeping in mind the stoichiometry, multiply FeCl3 with 2 to equate the Iron atoms.
- Fe2O3 + HCl = 2FeCl3 + H2O
- Step 3: Equate the Oxygen atoms per unit of the compound.
- Fe2O3 + HCl = 2FeCl3 + 3H2O
- Step 4: Since product side has 6 chlorine atoms per unit, the reaction should be equaled with the same number.
- Fe2O3 + 6HCl = 2FeCl3 + 3H2O
HCl + Fe2O3 Titration
The measurement of Fe2O3 is performed by a method called gravimetric analysis, primarily involving hydrochloric acid solution. Following is the overall procedure required with specific apparatus:
Apparatus Used
- Conical flask
- Beakers
- Filter Paper
- Bunsen Burner
Procedure
- The oxide is solvated in the hydrochloric acid medium in a conical flask.
- The conical flask is heated with ammonia and a few drops of dilute nitric acid are added. The solution is stirred for some time.
- The medium is washed to keep away impurities and it is repeated.
- The solution is filtered and washed again.
- A sticky reddish precipitate is obtained which is soluble in dilute acids
- It is heated and dried to measure purity. Any pieces of filter paper are added and the process is repeated.
- The amount of Ferric oxide obtained is measured,
- Weight of Iron is found by mathematical calculations.
HCl + Fe2O3 Net Ionic Equation
HCl + Fe2O3 net ionic equation stands as the formation of Iron(III) ions and Chloride ions along with the proton and hydroxyl ions from water.
- 2Fe2+(aq) + 3O2-(aq) + H+(aq) + Cl–(aq) = 2Fe3+(aq)+ 3Cl–(aq) + H+(aq) + OH–(aq)
HCl + Fe2O3 Conjugate Pairs
Conjugate acid-base pairs refer to those pairs of compounds where the chemical difference between them is just one proton. For instance,
- Conjugate base of HCl= Cl–
- Conjugate base of H2O = OH–
HCl and Fe2O3 Intermolecular Forces
HCl shows ionic interactions in an aqueous medium. On comparing electronegativity values, Fe2O3 is found to be polar covalent in nature due to small size of Fe3+ ion. FeCl3 produces electrostatic interactions, with London dispersion forces due to polarization of electron cloud in chlorine.
| Element | Electronegativity(approx.) |
|---|---|
| Iron | 1.8 |
| Oxygen | 3.5 |
| Hydrogen | 2.1 |
| Chlorine | 3.0 |
HCl + Fe2O3 Reaction Enthalpy
Reaction Enthalpy of HCl + Fe2O3 reaction is -281 kJ/mol. The reaction enthalpy can be found if individual enthalpy of formations are observed. The enthalpy information is as follows:
- Enthalpy of Formation of Fe2O3 = -822.0 kJ/mol
- Enthalpy of Formation of HCl = -92.3 kJ/mol
- Enthalpy of Formation of FeCl3 = -399.5 kJ/mol
- Enthalpy of Formation of H2O = -285.8 kJ/mol
Is HCl + Fe2O3 a Buffer Solution?
HCl + Fe2O3 combination will not yield a strong buffer solution as a strong acid like hydrochloric acid is already present.
Is HCl + Fe2O3 a Complete Reaction?
HCl + Fe2O3 is complete as complete products are formed at the end once equilibrium is reached.
Is HCl + Fe2O3 an Exothermic Reaction?
The HCl + Fe2O3 reaction is exothermic in nature as the reaction enthalpy is negative, thereby, increasing the temperature of the system.
Is HCl + Fe2O3 a Redox Reaction?
The reaction of HCl and Fe2O3 cannot be termed redox as it does not involve any change In oxidation state of the elements to the product side.
Is HCl + Fe2O3 a Precipitation Reaction?
HCl + Fe2O3 is not a precipitation reaction as the product does not precipitate in the system as an insoluble solid.
Is HCl + Fe2O3 a Reversible Reaction?
HCl + Fe2O3 is not reversible in nature as complete products are formed which cannot revert unless there is a change in temperature and pressure or other conditions.
Is HCl + Fe2O3 a Displacement Reaction?
The reaction of Hydrochloric acid with Ferric Oxide is a double displacement reaction.
Conclusion
Reaction of hydrochloric acid with ferric oxide produces an orange-red solution of ferric chloride which is oxidising in nature. The oxidation state of Fe remains unchanged. Ferric chloride is dubbed as “salt” as a result of neutralisation.
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