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
- The overall balanced equation will be,
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+ + SO42- + Mn4+ + 2O2- = Mn2+ + SO42- + 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 O2-.
- After that, the product MnSO4 also dissociates to Mn2+ which is d5 stable configuration and corresponding SO42-.
- 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 = SO42-
- 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.
Molecule | Acting force |
H2SO4 | Electrostatic, van der waal’s Dipole interaction |
MnO2 | Ionic, and electrostatic |
MnSO4 | Coulombic force, strong ionic interaction |
H2O | Covalent, H-bonding |
O2 | Van der waal’s force and London’s force |
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.
Molecule | Enthalpy (KJ/mol) |
MnO2 | -520 |
H2SO4 | -814 |
MnSO4 | -220.83 |
H2O | -68 |
O2 | 0 |
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.
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.