Manganese dioxide is the oxide of Manganese with a +4 Oxidation state. It reacts with HI in normal conditions. Let us discuss the reaction involved between HI and MnO2.
MnO2 is an inorganic compound having a black, brown appearance. MnO2 is used as a pigment in KMnO4. HI is strong colorless acid. Strong acid and basic oxide reactions are carried out without any catalyst.
The reaction between HI and MnO2 occurs in normal conditions. This article discusses the product formed from HI+ MnO2, net ionic equation, equation reaction, type reversible reaction, or Irreversible reaction.
What is the product of HI and MnO2 ?
The reaction between HI+ MnO2 is carried out, and water, iodine, and manganese (II) iodide are produced.
HI+ MnO2 –> MnI2 + H2O + I2.
What type of reaction are HI+ MnO2 ?
HI + MnO2 is a redox reaction where Mn4+ gets reduced to Mn2+ and I– gets oxidized to I.
How to balance HI and MnO2?
- MnO2 + 4HI –> MnI2 + 2H2O + I2 is the balanced chemical equation.
- The equation is balanced, as shown below. The table represents the number of moles of elements on the reactants and products side:
| Elements | Reactants | Products |
|---|---|---|
| Mn | 1 | 1 |
| O | 1 | 2 |
| H | 1 | 2 |
| I | 1 | 4 |
- The number of moles of O element is not balanced, so O is multiplied by 2 on the reactant side, making it equal to the product side.
- The number of moles of the H atom on the product side is 4, so the H atom on the reactants side is multiplied by 4 to balance the number.
- In the final step, it is observed that all elements from each side get balanced.
- The balanced equation is MnO2 + 4 HI –> MnI2 + 2H2O + I2.
HI + MnO2 titration
To estimate the quantity of Manganese, titration between HI and MnO2 is carried out as follows:
Apparatus used
Burette, conical flask, wash bottle, burette stand, volumetric flask, beakers.
Indicator
The complete titration is carried out in an acidic medium. The titration of MnO2 acts as a self-indicator because it is a colored solution, and the endpoint is noted with the color change.
Procedure
- The burette is filled with standardized HI.
- MnO2 is taken in a conical flask, and the measure is noted.
- The HI-filled-in burette is made to add to the conical flask dropwise with constant stirring.
- After some time, a pink color is observed, denoting the endpoint.
- Repeat the above steps for three more values and note the final result.
- Calculate the quantity of Manganese by using the formula V1S1= V2S2.
HI + MnO2 net ionic equation
- The phase of elements in the net ionic equation of the HI + MnO2 reaction is:
Mn4+(aq) –> Mn2+(aq) + 2I(g).
- The compounds are shown in their state present and their ionic form as shown below:
Mn4+(aq)+ 2O2- (aq)+ 4H+(aq)+ 4I–(aq) –> Mn2+(aq)+4I– (aq) + 2I(g) + 4H+(aq)+2O2-(aq).
- The same element elements with equal charges are canceled, and the final net ionic equation is
Mn4+(aq) –> Mn2+(aq) + 2I(g).
Is HI + MnO2 a conjugate pair?
The Conjugate pair of HI is I2 and the conjugate pair of OH– is H2O. HI and MnO2 form an acid-base conjugate pair by donating a Proton from a strong acid and accepting a Proton from the base.
HI+ is MnO2 intermolecular forces
- The intermolecular forces present in MnO2 are ionic and electrostatic.
- HI has hydrogen bonding London-dispersion and dipole-dipole intermolecular force.
- MnI2 has ionic and electrostatic intermolecular forces.
- I2 has Vander Waals dispersion force.
- Hydrogen bond, dipole induced, dipole- London dispersion forces are present in the water molecule.
HI + MnO2 reaction enthalpy
The reaction enthalpy of HI and MnO2 is + 433 kJ/mol.
The table below represents the standard enthalpy of the formation of the molecule.
| Molecules | Reaction enthalpy(KJ/mol) |
|---|---|
| MnO2 | -520 |
| HI | 26.5 |
| MnI2 | -54.5 |
| H2O | -68 |
| I2 | 62.8 |
Reaction enthalpy= (standard enthalpy of formation of products) – (standard enthalpy of formation of reactants).
Is HI+ MnO2 a buffer solution
HI and MnO2 do not form a buffer solution because HI is a strong acid, and buffer solutions are formed from a weak acid and its respective conjugate base.
Is HI+ MnO2 a complete reaction
HI and MnO2 is a complete reaction because the products formed cannot be converted back to the reactant, and no more products are formed from the reaction.
Is HI+ MnO2 an exothermic or endothermic reaction
HI and MnO2 are endothermic reactions because the reaction enthalpy value is positive.
Is HI+ MnO2 a redox reaction
The reaction between HI and MnO2 is a redox reaction as Mn4+ gets reduced to Mn2+, and 2I– gets oxidized to 2I. MnO2 acts as an oxidizing agent, and HI acts as a reducing agent.
Is HI + MnO2 a precipitation reaction
The reaction between HI and MnO2 is a precipitation reaction because the MnI2 formed in the reaction is pink crystalline.
Is HI+ MnO2 a reversible reaction or an irreversible reaction
The reaction between HI and MnO2 is irreversible because iodine gas is formed and cannot be reversed back.
Is HI+ MnO2 a displacement reaction
The reaction between HI and MnO2 is a double displacement reaction because Mn displaces I from HI, and O gets displaced to H from MnO2.
Conclusion
HI and MnO2 react to give MnI2, H2O, and I2. This reaction is useful for producing iodine gas. Manganese dioxide is used as a pigment in compounds like KMnO4 and for synthesizing various organic compounds. Manganese dioxide is mainly used to manufacture dry-cell batteries.
Hello…I am Manjula Sivapuri. I have completed my graduation in Chemistry. Currently working as a Chemistry Subject Matter expert in LambdaGeeks. My keen interest in chemistry has brought me to this platform to share my knowledge on the subject. I hope my work will make you understand the topics well.
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