15 Facts on H2SO4 + Mn2O7: What, How To Balance & FAQs

Mn₂O₇ is an acidic molecule so it can react with acid molecules stronger. Let us see what happens when H₂SO₄ reacts with Mn₂O₇.

In Mn₂O₇, the oxidation state of Mn is +7, so it is the most oxidizing agent and can undergo reduction and can oxidize other elements or molecules. The molecule is also known as manganese heptaoxide where the Mn-O-Mn bond is observed along with double-bonded oxygen.

The reaction between Mn₂O₇ and H₂SO₄ does not require any kind of catalyst or temperature. Let us discuss the mechanism of the reaction between sulfuric acid and manganese, 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 Mn₂O₇?

Manganese sulfate is formed as the major product when H₂SO₄ and Mn₂O₇ are reacted together along with water molecules.

H₂SO₄ + Mn₂O₇ = Mn₂(SO₄)₇ + H₂O

2. What type of reaction is H₂SO₄ + Mn₂O₇?

The reaction between H₂SO₄ + Mn₂O₇ is an example of a double displacement reaction along with redox and precipitation reactions. It is also a hydrolysis reaction.

3. How to balance H₂SO₄ + Mn₂O₇?

We have to balance the equation, H₂SO₄ + Mn₂O₇ = Mn₂(SO₄)₇ + H₂O in the following way:

• First, we label all the reactants and products by A, B, C, D, and E as there are only five different atoms obtained for this reaction and the reaction looks like this: A H₂SO₄ + B Mn₂O₇ = C Mn₂(SO₄)₇ + D H₂O
• 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 = 7C, O = 4A = 7B = 28C = D, Mn = 2B = 2C
• Using the Gaussian elimination and equating all the equations we get, A = 7, B = 1, C = 1, and D = 7
• Now write the whole equation in the balanced form
•  The overall balanced equation will be,
  7H₂SO₄ + Mn₂O₇ = Mn₂(SO₄)₇ + 7H₂O

4. H₂SO₄ + Mn₂O₇ titration

To estimate the quantity of manganese we can perform a titration between Mn₂O₇ and H₂SO₄

Apparatus used

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

Titre and titrant

H₂SO₄ acts as a titrant which is taken in the burette and the molecule to be analyzed is Mn₂O₇ which is taken in a conical flask.

Indicator

The whole titration is done in acidic pH as the concentration of H₂SO₄ is high and for this reaction, Mn₂O₇ acts as a self-indicator because it is a colored solution and in different pH, it changes color.

Procedure

The burette was filled with standardized H₂SO₄ and Mn₂O₇ 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, Mn₂O₇ changes its color.

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

5. H₂SO₄+ Mn₂O₇ net ionic equation

The net ionic equation between H₂SO₄ + Mn₂O₇ is as follows,

14H⁺ + 7SO₄^2- + 2Mn²⁺ + 7O^2- = 2Mn²⁺ + 7SO₄^2- + H⁺ + OH^–

To derive the net ionic equation the following steps are required,

• First H₂SO₄ will be ionized in proton and sulfate ions as it is a strong electrolyte
• After that Mn₂O₇ also dissociates to Mn²⁺ ion and O^2-.
• After that, the product Mn₂(SO₄)₇ also dissociates to Mn²⁺ which is d⁵ stable configuration and corresponding SO₄^2-.
• Water is also ionized to H⁺ and OH^-.

6. H₂SO₄+ Mn₂O₇ conjugate pairs

H₂SO₄ + Mn₂O₇ 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 OH^– = H₂O

7. H₂SO₄ and Mn₂O₇ intermolecular forces

The intermolecular force between H₂SO₄ is an electrostatic, covalent force. For Mn₂O₇, it is ionic interaction, and peroxy linkage is present. In Mn₂(SO₄)₇, strong ionic interactions are present along with dipole force and for water, H-bonding is present.

8. H₂SO₄ + Mn₂O₇ reaction enthalpy

H₂SO₄ + Mn₂O₇  reaction enthalpy is -5428 KJ/mol which can be obtained by the formula enthalpy of products – enthalpy of reactants, and here the change in enthalpy is negative.

9. Is H₂SO₄ + Mn₂O₇ a buffer solution?

The reaction between H₂SO₄ + Mn₂O₇ gives a buffer solution and they can control the pH of the solution.

10. Is H₂SO₄ + Mn₂O₇ a complete reaction?

The reaction between H₂SO₄ + Mn₂O₇ is a complete reaction because it gives one complete product Mn₂(SO₄)₇ along with the water molecule.

11. Is H₂SO₄ + Mn₂O₇ an exothermic or endothermic reaction?

The reaction H₂SO₄ + Mn₂O₇ is exothermic in terms of thermodynamics first law. So, the reaction releases more energy and temperature to the surrounding so we have to be more cautious, where δH is always negative.

12. Is H₂SO₄ + Mn₂O₇ a redox reaction?

The reaction between H₂SO₄ + Mn₂O₇ is a redox reaction because in this reaction many elements get reduced and oxidized. Here, Mn gets reduced and S gets oxidized.

13. Is H₂SO₄ + Mn₂O₇ a precipitation reaction

The reaction H₂SO₄ + Mn₂O₇ is a precipitation reaction because Mn₂(SO₄)₇ gets precipitated in the solution and is not a soluble in the reaction mixture.

14. Is H₂SO₄ + Mn₂O₇ reversible or irreversible reaction?

The reaction between H₂SO₄+ Mn₂O₇ is irreversible because we get Mn₂(SO₄)₇ as a major product and the equilibrium of the reaction is shifted toward right hand side. Also, we can say the reaction goes to the forward direction only.

15. Is H₂SO₄ + Mn₂O₇ displacement reaction?

The reaction between H₂SO₄+ Mn₂O₇ is an example of a double displacement reaction because in the above reaction Mn displaced  H⁺ in H₂SO₄ and H⁺ also displaced Mn from Mn₂O₇.

Conclusion

H₂SO₄ and Mn₂O₇ reaction mainly gives us Mn₂(SO₄)₇ along with water molecule. So, using this reaction we can produce manganese sulfate, and Mn₂O₇ acts as strong oxidising agent here.

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.