The reaction between H2SO4 and Fe(OH)3 follows an inorganic mechanism where the latter is a weak base rather electrolyte. Let us see the reaction of H2SO4 and Fe(OH)3 in deatil.
Ferric hydroxide is the weak base where iron is present at the +3 oxidation state. So, it can react with a strong acid like sulfuric acid and form corresponding salt and water. There is also a hydrated part present in the ferric oxide so when it reacts with sulfuric acid, the acid absorbs the water.
By the reaction between Fe(OH)3 and H2SO4, we can estimate the quantity of iron in the respective sample. 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(OH)3?
Ferric sulfate is a major product formed when H2SO4 and Fe(OH)3 are reacted together along with water molecules. Fe is present in a higher position than hydrogen in the electrochemical series so the corresponding sulfate is formed.
H2SO4 and Fe(OH)3
2. What type of reaction is H2SO4 + Fe(OH)3?
H2SO4 + Fe(OH)3 reaction is an example of a neutralization reaction and single displacement reaction along with redox and precipitation reactions. Here, acid compounds neutralize alkali compounds feebly and forms salt and water.
3. How to balance H2SO4 + Fe(OH)3?
H2SO4 + Fe(OH)3 = Fe2(SO4)3 + H2O this reaction is not balanced yet, we have to balance the equation in the following way-
- First, we label 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(OH)3 = C Fe2(SO4)3 + D H2O
- Equating the coefficients for the same type of elements by rearranging them.
- After the rearrangement of coefficients of the same elements by their stoichiometric proportion, we get, H = 2A = 2D, S = A = 3C, O = 4A = 3C = 12C = 2D, Fe = B = 2C.
- Using the Gaussian elimination and equating all the equations we get, A = 3, B = 2, C = 1, and D = 6, so the oxidation number of Fe is +2 on both sides.
- The overall balanced equation will be,
3H2SO4 + 2Fe(OH)3 = Fe2(SO4)3 + 6H2O
4. H2SO4 + Fe(OH)3 titration
To estimate the quantity of sulfur or copper we can perform a titration between Fe(OH)3 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(OH)3, 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 is filled with standardized H2SO4. Fe is taken in a conical flask along with respective indicators. H2SO4 is added dropwise to the conical flask and the flask is shaken constantly. After a certain time, when the endpoint arrives, indicator changes its color and the reaction is 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(OH)3 net ionic equation
The net ionic equation between H2SO4 + Fe(OH)3 is as follows,
2H+ + SO42- + Fe3+ + 3OH– = 2Fe3+ + 3SO42- + H+ + OH–
To derive the net ionic equation, the following steps are required,
- H2SO4 will be ionized in proton and sulfate ions as it is a strong electrolyte
- After that Fe(OH)3 also dissociates into ferric ions and hydroxide ions as it is also a weak electrolyte
- And lastly, water is ionized into H+ and OH– by dissociation.
6. H2SO4+ Fe(OH)3 conjugate pairs
In the reaction, H2SO4 + Fe(OH)3 conjugate pairs will be the corresponding de-protonated and protonated form of that particular species which are listed below-
- Conjugate pair of H2SO4 = SO42-
- Conjugate pair of OH– = H2O
7. H2SO4 and Fe(OH)3 intermolecular forces
The intermolecular force present in H2SO4 is the strong electrostatic force between protons and sulfate ions. Also due to polarity, some Van der Waal’s force of 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.
| Molecule | Acting force |
| H2SO4 | Electrostatic, van der waal’s Dipole interaction |
| Fe(OH)3 | Strong electrostatic force and ionic interaction |
| Fe2(SO4)3 | Columbia force, ionic interaction, metallic bond |
| H2O | Covalent, H-bonding |
8. H2SO4 + Fe(OH)3 reaction enthalpy
H2SO4 + Fe reaction enthalpy is -1353 KJ/mol which can be obtained by the formula: enthalpy of products – enthalpy of reactants. Here the change in enthalpy is positive.
| Molecule | Enthalpy (KJ/mol) |
| Fe(OH)3 | -824 |
| H2SO4 | -814 |
| Fe2(SO4)3 | -2583 |
| H2O | -68 |
and Products
9. Is H2SO4 + Fe(OH)3 a buffer solution?
The reaction between H2SO4 + Fe(OH)3 gives a buffer solution of Fe2(SO4)3 and H2O and they can control the pH of the reaction.
10. Is H2SO4 + Fe(OH)3 a complete reaction?
The reaction between H2SO4 + Fe is a complete reaction because it gives one complete product Fe2(SO4)3 along with H2O.
11. Is H2SO4 + Fe(OH)3 an exothermic or endothermic reaction?
The reaction of H2SO4 + Fe(OH)3 is exothermic in terms of thermodynamics first law. This reaction releases more energy and temperature to the surroundings which helps to complete the reaction, Where δH is always negative.
12. Is H2SO4 + Fe(OH)3 a redox reaction?
H2SO4 + Fe(OH)3 reaction is a redox reaction because in this reaction many elements get reduced and oxidized as iron gets reduced and sulfur gets oxidized.
H2SO4 and Fe Reaction
13. Is H2SO4 + Fe(OH)3 a precipitation reaction
The reaction H2SO4 + Fe(OH)3 is a precipitation reaction because Fe2(SO4)3 gets precipitated in the solution and is not soluble in the reaction mixture.
14. Is H2SO4 + Fe(OH)3 reversible or irreversible reaction?
The reaction between H2SO4+ Fe(OH)3 is reversible because it is one kind of acid-base reaction. Where the produced salt can react with water and can proceed with the reaction in the backward direction. Where the equilibrium is shifted in the forward direction.
15. Is H2SO4 + Fe(OH)3 displacement reaction?
The reaction between H2SO4+ Fe(OH)3 is an example of double displacement reaction because in the above reaction Fe3+ displaced H+ in H2SO4 and H+ displaced Fe3+ in Fe(OH)3.
Conclusion
The reaction between H2SO4 and Fe(OH)3 gives us a electrolytic salt ferric sulfate where we can estimate the amount of iron present. This reaction is acid-base and reversible reaction, so it can again formed the acid and base which is economically friendly.
Read more facts on H2SO4:
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.
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