15 Facts on H2SO4 + Fe: What, How To Balance & FAQs

H₂SO₄ is a strong acid and it can react with many more transition metals. Let us see the mechanism behind the reaction H₂SO₄ + Fe.

Iron is placed higher postion in electrochemical series than hydrogen, so it has higher reduction potential. Sulfuric acid is one of strong mineral inorganic acids and also a powerful oxidizing agent. Sulfuric acid has a greater affinity with water molecule and produce heat when it reacts with water.

To estimate the quantity of iron we can perform the reaction between Fe and H₂SO₄ or estimate the quantity of sulfate also. Let us discuss the mechanism of the reaction between sulfuric acid and iron, the reaction enthalpy, the type of reaction, product formation, etc in the following part of the article.

1. What is the product of H₂SO₄ and Fe?

Ferrous sulfate is a major product formed when H₂SO₄ and Fe are reacted together and hydrogen gas is liberated. Fe is present in a higher position than hydrogen in the electrochemical series so the corresponding sulfate is formed.

2. What type of reaction is H₂SO₄ + Fe?

H₂SO₄ + Fe reaction is an example of a single displacement reaction along with redox and precipitation reactions. Here higher reduction potential element reacted with the acid molecule.

3. How to balance H₂SO₄ + Fe?

H₂SO₄ + Fe = FeSO₄ + H₂ this reaction is not balanced by the oxidation number because iron shows different valency which is not equal for the left side and right side. We have to balance the equation in the following way,

• Step 1 – Labelling all the reactants and products by the required number of alphabets

• First, we labeled all the reactants and products by A, B, C, and D as there are only four molecules obtained for this reaction and the reaction looks like: A H₂SO₄ + B Fe = C FeSO₄ + D H₂  
• Step 2 – Equating all the Coefficients for all the same type of elements by rearranging them
• After the rearrangement of all the coefficients of the same elements by their stoichiometric proportion we get, H = 2A = 2D, S = A = C, O = 4A = 4C, Fe = B = C
• Step 3 – Using Gaussian elimination to determine the coefficient values
• Using the Gaussian elimination and equating all the equations we get, A = 1, B = 1, C = 1, and D = 1, so the oxidation number of Fe is +2 on both sides.
• Step 4- now write the whole equation in the balanced form
•  The overall balanced equation will be,

H₂SO₄ + Fe = FeSO₄ + H₂

4. H₂SO₄ + Fe titration

To estimate the quantity of sulfur or copper, we can perform a titration between Fe and H₂SO₄

Apparatus used

We need a burette, conical flask, burette holder, volumetric flask, and beakers for this titration.

Titre and titrant

H₂SO₄ versus Fe, H2SO4 acts as a titrant which is taken in the burette and the molecule to be analyzed is Fe which is taken in a conical flask.

Indicator

The whole titration is done in an acidic medium or acidic pH so the best suitable indicator will be phenolphthalein which gives perfect results for this titration at given pH.

Procedure

The burette was filled with standardized H₂SO₄ and Fe was taken in a conical flask along with the respective indicator. H₂SO₄ is added dropwise to the conical flask and the flask was shaking constantly. After a certain time when the endpoint arrived indicator changes its color and the reaction was done.

We repeat the titration several times for better results and then we estimate the iron as well as sulfate quantity by the formula V₁S₁ = V₂S₂.

5. H₂SO₄+ Fe net ionic equation

The net ionic equation between H₂SO₄ + Fe is as follows,

2H⁺ + SO₄^2- + Fe²⁺ + 2e^– = Fe²⁺ + SO₄^2- + H₂

6. H₂SO₄+ Fe conjugate pairs

In the reaction, H₂SO₄ + Fe conjugate pairs will be the corresponding de-protonated and protonated form of that particular species which are listed below-

• Conjugate pair of H₂SO₄ = SO₄^2-
• Conjugate pair of H^– = H₂

7. H₂SO₄ and Fe intermolecular forces

The intermolecular force present in H₂SO₄ is due to the strong electrostatic force between proton and sulfate ions. Also due to polarity, van der waal’s attraction is present but in the case of H₂, covalent force, as well as dipole interaction is present, and for FeSO₄ only covalent force is present.

8. H₂SO₄ + Fe reaction enthalpy

In the reaction, H₂SO₄ + Fe reaction enthalpy is,+131.34 KJ/mol which can be obtained by the formula enthalpy of products – enthalpy of reactants, and here the change in enthalpy is positive.

9. Is H₂SO₄ + Fe a buffer solution?

The reaction between H₂SO₄ + Fe gives a buffer solution of FeSO₄ and H₂ and they can control the pH of the reaction.

10. Is H₂SO₄ + Fe a complete reaction?

The reaction H₂SO₄ + Fe is the complete reaction because it gives one complete product FeSO₄ along with H₂ gas. The reaction takes need some time to complete until all the reactants completely reacted the products are not formed.

11. Is H₂SO₄ + Fe an exothermic or endothermic reaction?

The reaction H₂SO₄ + Fe is endothermic in terms of thermodynamics first law. So, the reaction takes more energy and temperature from the surroundings which help to complete the reaction, Where δH is always positive.

12. Is H₂SO₄ + Fe a redox reaction?

H₂SO₄ + Fe reaction is a redox reaction because in this reaction many elements get reduced and oxidized as hydrogen gets reduced and Fe gets oxidized.

13. Is H₂SO₄ + Fe a precipitation reaction

The reaction H₂SO₄ + Fe is a precipitation reaction because FeSO₄ gets precipitated in the solution and is not soluble in the reaction mixture.

14. Is H₂SO₄ + Fe reversible or irreversible reaction?

The reaction between H₂SO₄+ Fe is irreversible because we get H₂ gas as a product. When gas is formed during the reaction the entropy of the reaction increases and the equilibrium of the reaction shifts towards the right-hand side only.

15. Is H₂SO₄ + Fe displacement reaction?

The reaction between H₂SO₄+ Fe is an example single displacement reaction because in the above reaction Fe²⁺ displaced H⁺ in H₂SO₄ only and H₂ gas becomes free from the reaction.

Conclusion

H₂SO₄ and Fe reaction mainly gives us ferrous sulfide along with hydrogen gas so it is a commercially important reaction for the production of hydrogen gas. Also, the quantitative analysis of the H₂SO₄ and Fe gives the amount of iron as well as sulfate in the respective sample.

Read more facts on H2SO4:

Biswarup Chandra Dey

Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.