15 Facts on H2SO4 + MnO2: What, How To Balance & FAQs

MnO₂ is a basic oxide of Mn having a lower oxidation state and it can react with H₂SO₄ at any condition. Let us see the reaction mechanism between H₂SO₄ and MnO₂.

Manganese dioxide is a reducing agent because of the oxidation number of Mn is +4 and can oxidation to increase its oxidation number and reduce other elements. MnO₂ can use in several ORR (oxygen reduction reactions) in plants or in vivo. Where H₂SO₄ has higher affinity to water molecules and rapidly reacts with it.

The reaction between MnO₂ and H₂SO₄ does not require a catalyst and even can occur in diluted conditions. 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 MnO₂?

Manganese sulfate is formed as the major product when H₂SO₄ and MnO₂ are reacted together along with water molecules and oxygen gas will be liberated.

H₂SO₄ + MnO₂ = MnSO₄ + H₂O + O₂

2. What type of reaction is H₂SO₄ + MnO₂?

The reaction between H₂SO₄ + MnO₂ is mainly a redox reaction along with displacement and precipitation reactions. It is also an acid-base neutralization reaction.

3. How to balance H₂SO₄ + MnO₂?

We have to balance the equation, 

H₂SO₄ + MnO2 = MnSO₄ + H₂O +O₂ 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 MnO₂ = C MnSO₄ + D H₂O + E O₂
• 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 = 2B = 4C = D = 2E, Mn = B = C
• Using the Gaussian elimination and equating all the equations we get, A = 2, B = 2, C = 2, D = 2, and E = 1.
• Now write the whole equation in the balanced form
  •  The overall balanced equation will be,
    2H₂SO₄ + 2MnO₂ = 2MnSO₄+ 2H₂O +O₂

4. H₂SO₄ + MnO₂ titration

To estimate the quantity of manganese we can perform a titration between MnO₂ 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 are MnO₂ 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, MnO₂ 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 MnO₂ 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, MnO₂ 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+ MnO₂ net ionic equation

The net ionic equation between H₂SO₄ + MnO₂ is as follows,

H⁺ + SO₄^2- + Mn⁴⁺ + 2O^2- = Mn²⁺ + SO₄^2- + H⁺ + OH^– + O₂
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 MnO₂ also dissociates to Mn⁴⁺ and O^2-.
• After that, the product MnSO₄ also dissociates to Mn²⁺ which is d⁵ stable configuration and corresponding SO₄^2-.
• Water is also ionized to H⁺ and OH^-.
• O₂ remains in its gaseous form.

6. H₂SO₄+ MnO2 conjugate pairs

H₂SO₄ + MnO₂ 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 MnO2 intermolecular forces

The intermolecular force between H₂SO₄ is an electrostatic, covalent force. For MnO₂, ionic interaction is present. In MnSO₄, strong ionic interactions are present along with dipole force, and for water, H-bonding is present and oxygen van der waal’s force is present.

8. H₂SO₄ + MnO₂ reaction enthalpy

H₂SO₄ + MnO₂  reaction enthalpy is -2088.34 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 + MnO₂ a buffer solution?

The reaction between H₂SO₄ + MnO₂ gives a buffer solution of MnSO₄ and H₂O and this mixture can control the pH of the whole solution even after adding acid.

10. Is H₂SO₄ + MnO₂ a complete reaction?

The reaction between H₂SO₄ + MnO₂ is complete because it gives one complete product MnSO₄ along with the water molecule and oxygen gas. So, the reactants get utilized.

11. Is H₂SO₄ + MnO₂ an exothermic or endothermic reaction?

The reaction H₂SO₄ + MnO₂ is exothermic in terms of thermodynamics first law. So, the reaction released energy and temperature to the surrounding which helps to proceed with the reaction, where δH is always negative.

12. Is H₂SO₄ + MnO₂ a redox reaction?

The reaction between H₂SO₄ + MnO₂ is a redox reaction because in this reaction many elements get reduced and oxidized. Here, Mn gets reduced and sulfur gets oxidized.

13. Is H₂SO₄ + MnO₂ a precipitation reaction

The reaction H₂SO₄ + MnO₂ is a precipitation reaction because MnSO₄ gets precipitated in the solution and is not soluble in the reaction mixture even in an acidic medium.

14. Is H₂SO₄ + MnO₂ reversible or irreversible reaction?

The reaction between H₂SO₄+ MnO₂ is irreversible because we get oxygen which is formed as gas. When a gaseous molecule is produced then the entropy of the reaction increases and the equilibrium shifts toward the right-hand side and proceeds in the forward direction.

15. Is H₂SO₄ + MnO₂ displacement reaction?

The reaction between H₂SO₄+ MnO₂ is an example of a double displacement reaction because in the reaction Mn displaced  H⁺ in H₂SO₄ and H⁺ also displaced Mn from MnO₂.

Conclusion

H₂SO₄ and MnO₂ reactions mainly give us MnSO₄ along with water and oxygen gas. So, this reaction is very much important for the production of oxygen gas. MnO₂ is one of the most important molecules for organometallic chemistry and it is under several reactions like ORR and evolved oxygen in vivo. MnO₂ is a non-stoichiometric deficient cluster having several vacant sites.

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.