15 Facts on H2SO4 + Fe2(CO3)3: What, How To Balance & FAQs

Sulfuric acid (H₂SO₄), known as “oil of vitriol,” is a strong inorganic acid, and Fe₂(CO₃)₃ (Ferric carbonate) is an insoluble salt. Let us investigate their reaction in detail.

A neutralization reaction occurs when Fe₂(CO₃)₃ reacts with H₂SO₄. Sulfuric acid is highly hygroscopic, absorbs moisture, and is corrosive by nature. Iron is present in the +3 oxidation state in ferric carbonate.

This article will explain the reaction type, balancing method, molecular forces, and other properties of the reaction between sulfuric acid and carbonate salt.

What is the product of H₂SO₄ and Fe₂(CO₃)₃

Fe₂(SO₄)₃ (Ferric sulfate) and carbon dioxide gas, along with water molecules are produced when Fe₂(CO₃)₃ combines with sulfuric acid.

H₂SO₄ + Fe₂(CO₃)₃ → Fe₂(SO₄)₃ + H₂O + CO₂

What type of reaction is H₂SO₄ + Fe₂(CO₃)₃

• Fe₂(CO₃)₃ + H₂SO₄ is a neutralization reaction as the carbonate and acid combine to give a salt.
• The reaction H₂SO₄ + Fe₂(CO₃)₃ starts with a double displacement reaction followed by a decomposition reaction.

How to balance H₂SO₄ + Fe₂(CO₃)₃

The equation H₂SO₄ + Fe₂(CO₃)₃ can be balanced in subsequent steps,

H₂SO₄ + Fe₂(CO₃)₃ → Fe₂(SO₄)₃ + H₂O + CO₂

• In the first step, the number and type of elements are counted in both reactants and the products.  
• Further, the stoichiometric coefficients are used before the substituents to balance the elements and charges. A coefficient of 3 is added before H₂SO_4, H₂O, and CO₂ respectively.
• Thus the balanced equation is
•  Fe₂(CO₃)₃ + 3H₂SO₄ → Fe₂(SO₄)₃ + 3H₂O + 3CO₂

H₂SO₄+ Fe₂(CO₃)₃ titration

Fe₂(CO₃)₃ is an insoluble carbonate, so back titration is performed as mentioned below. In this titration, an excess of standard solution is added and titrated, which is very useful for non-soluble solids.

Apparatus

Volumetric flask, beaker, funnel, burette, conical flask, pipette

Indicator

Phenolphthalein is used as an indicator here.

Procedure

• A known amount of Fe₂(CO₃)₃ is weighed. To this, sulfuric acid is added and mixed thoroughly to make a homogenous solution and then the solution is transferred to a volumetric flask. With the use of distilled water, the solution is made up to the mark.
• 15 ml of the prepared solution is taken in the flask with the help of a pipette and two to three drops of the indicator are added to it.
• The resultant solution is titrated against a standard NaOH solution, which is taken in the burette.
• The color change is observed and the endpoint is attained at the light pink color of the solution.
• The concordant readings are taken which are used in calculating the concentration of the carbonate.

H₂SO₄ + Fe₂(CO₃)₃ net ionic equation

The net ionic equation is

Fe₂(CO₃)₃(s) + 6H⁺(aq) → 2Fe³⁺(aq) + 3H₂O(l) + 3CO₂(g)

This above equation can be derived by the following steps,

• The balanced equation is written in the first step. From our previous calculation, the balanced equation is
• Fe₂(CO₃)₃ + 3H₂SO₄ → Fe₂(SO₄)₃ + 3H₂O + 3CO₂
• In the next step, the phases of all the components of the reaction are shown. So, now the equation becomes
• Fe₂(CO₃)₃(s) + 3H₂SO₄(aq) → Fe₂(SO₄)₃(s) + 3H₂O(l) + 3CO₂(g)
• The strong-electrolytes are further split into their corresponding ions. H₂O is a weak-electrolyte so it will not split.
• Fe₂(CO₃)₃(s) + 6H⁺ + 3SO₄^2-(aq) → 2Fe³⁺(aq) +3SO₄^2-(aq) + 3H₂O(l) + 3CO₂(g)
• The common ions are crossed out and the resulting net ionic equation of this reaction.

H₂SO₄ + Fe₂(CO₃)₃ conjugate pairs

H₂SO₄-Fe₂(CO₃)₃ can form a conjugate acid-base pair.

• H₂SO₄ forms SO₄^2- ion as its conjugate base.

• The carbonate ion (CO₃^2-) acts as a base, it accepts H⁺ and forms its conjugate acid (H₂CO₃).

H₂SO₄ and Fe₂(CO₃)₃ intermolecular forces

• Fe₂(CO₃)₃ has electrostatic force of attraction as the molecules are ionic in nature.
• Hydrogen bonding, dipole-dipole interactions, and dispersion forces are present in H₂SO₄ where Hydrogen bonding interactions are the strongest.

H₂SO₄ + Fe₂(CO₃)₃ reaction enthalpy

The enthalpy of this reaction is found to be -591.19 KJ/mol. From the listed values, we can calculate the enthalpy.

• ∆H_f^°(reaction) = ∆H_f^°(products) – ∆H_f^°(reactants)
• Therefore, ∆H_f^°(reaction) = -4801.3 – (- 4210.11) KJ/mol
• Thus, ∆H_f^°(reaction) = -591.19 KJ/mol

Is H₂SO₄ + Fe₂(CO₃)₃ a buffer solution

The combination Fe₂(CO₃)₃+H₂SO₄ will not form a buffer solution due to the presence of a strong acid (H₂SO₄).

Is H₂SO₄ + Fe₂(CO₃)₃ a complete reaction

The reaction Fe₂(CO₃)₃ + H₂SO₄ is a complete reaction because completely decomposed products are formed, which will not react further.

Is H₂SO₄ + Fe₂(CO₃)₃ an exothermic or endothermic reaction

Fe₂(CO₃)₃ + H₂SO₄ is an exothermic reaction as the enthalpy is negative for the reaction. Also, the products are quite stable, so a lot of heat is produced during the reaction.

Is H₂SO₄+ Fe₂(CO₃)₃ a redox reaction

H₂SO₄ + Fe₂(CO₃)₃ is not a redox reaction as the oxidation states of the elements are not being changed.

Is H₂SO₄ + Fe₂(CO₃)₃ a precipitation reaction

H₂SO₄ + Fe₂(CO₃)₃ is not a precipitation reaction as the iron sulfate produced in the reaction is soluble, hence no precipitate is obtained.

Is H₂SO₄ + Fe₂(CO₃)₃ reversible or irreversible reaction

Fe₂(CO₃)₃ + H₂SO₄ reaction is an irreversible reaction as there is an increase in entropy for the forward reaction due to the formation of CO₂ gas. Also because, the products formed will not react to give back the reactants.

Is H₂SO₄ + Fe₂(CO₃)₃ displacement reaction

The first step of the reaction Fe₂(CO₃)₃+H₂SO₄ is a double displacement reaction. Since Fe is more reactive, it displaces hydrogen from its salt and forms iron sulfate, and the H⁺ combines with carbonate ions to form carbonic acid.

H₂SO₄ + Fe₂(CO₃)₃ = Fe₂(SO₄)₃ + H₂CO₃

Conclusion

Sulfuric acid is widely used as a dehydrating agent in synthetic organic chemistry. Carbon dioxide obtained in the reaction is a colorless acidic gas, 50% denser than air, and an infrared-active molecule. CO₂ is a greenhouse gas, and its high concentration leads to global warming.