H_{2}SO_{4} is a strong acid and it can react with many more transition metals. Let us see the mechanism behind the reaction H_{2}SO_{4} + Fe.

**Iron is placed higher postion in electrochemical series than hydrogen, so it has higher reduction potential. Sulfuric acid is one of strong mineral inorganic acids and also a powerful oxidizing agent**. **Sulfuric acid has a greater affinity with water molecule and produce heat when it reacts with water.**

To estimate the quantity of iron we can perform the reaction between Fe and H_{2}SO_{4} or estimate the quantity of sulfate also**. **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 H_{2}SO_{4} and Fe?

**Ferrous sulfate is a major product formed when H _{2}SO_{4} and Fe are reacted together and hydrogen gas is liberated. Fe is present in a higher position than hydrogen in the electrochemical series so the corresponding sulfate is formed.**

## 2. What type of reaction is H_{2}SO_{4} + Fe?

**H _{2}SO_{4}**

**+ Fe reaction is an example of a single displacement reaction along with redox and precipitation reactions. Here higher reduction potential element reacted with the acid molecule.**

## 3. How to balance H_{2}SO_{4} + Fe?

**H _{2}SO_{4}**

**+ Fe = FeSO**

_{4}+ H_{2}this reaction is not balanced by the oxidation number because iron shows different valency which is not equal for the left side and right side. We have to balance the equation in the following way,**Step 1 – Labelling all the reactants and products by the required number of alphabets**

**First, we labeled 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 H**_{2}SO_{4}+ B Fe = C FeSO_{4}+ D H_{2}**Step 2 – 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 = 4C, Fe = B = C****Step 3 – Using Gaussian elimination to determine the coefficient values****Using the Gaussian elimination and equating all the equations we get, A = 1, B = 1, C = 1, and D = 1, so the oxidation number of Fe is +2 on both sides.****Step 4- now write the whole equation in the balanced form****The overall balanced equation will be,**

**H _{2}SO_{4}**

**+ Fe = FeSO**

_{4}+ H_{2}## 4. H_{2}SO_{4} + Fe titration

**To estimate the quantity of sulfur or copper, we can perform a titration between Fe and ****H _{2}SO_{4}**

### Apparatus used

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

### Titre and titrant

**H _{2}SO_{4}**

**versus Fe,**

**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 was filled with standardized ****H _{2}SO_{4}**

**and Fe was taken in a conical flask along with the respective indicator.**

**H**

_{2}SO_{4}**is added dropwise to the conical flask and the flask was shaking constantly. After a certain time when the endpoint arrived indicator changes its color and the reaction was done.**

We repeat the titration several times for better results and then we estimate the iron as well as sulfate quantity by the formula V_{1}S_{1 }= V_{2}S_{2}.

## 5. H_{2}SO_{4}+ Fe net ionic equation

**The net ionic equation between ****H _{2}SO_{4}**

**+ Fe is as follows,**

**2H**^{+}** + SO _{4}^{2-} + **

**Fe**

^{2+}+ 2e^{–}**= Fe**

^{2+}+ SO_{4}^{2-}+ H_{2}## 6. H_{2}SO_{4}+ Fe conjugate pairs

**In the reaction, H _{2}SO_{4}**

**+ Fe conjugate pairs will be the corresponding de-protonated and protonated form of that particular species which are listed below-**

**Conjugate pair of****H**_{2}SO_{4}**= SO**_{4}^{2-}**Conjugate pair of H**^{–}=**H**_{2}

## 7. H_{2}SO_{4} and Fe intermolecular forces

**The intermolecular force present in ****H _{2}SO_{4}**

**is due to the strong electrostatic force between proton and sulfate ions. Also due to polarity, van der waal’s attraction is present but in the case of H**

_{2}, covalent force, as well as dipole interaction is present, and for FeSO_{4}only covalent force is present.Molecule | Actingforce |

H_{2}SO_{4} | Electrostatic, van der waal’s Dipole interaction |

Fe | Covalent, metallic bond |

FeSO_{4} | Columbia force, ionic interaction |

H_{2} | Covalent, H-bonding |

**Intermolecular Forces**

## 8. H_{2}SO_{4} + Fe reaction enthalpy

**In the reaction, H _{2}SO_{4}**

**+ Fe**

**reaction enthalpy**

**is,+131.34 KJ/mol which can be obtained by the formula enthalpy of products – enthalpy of reactants, and here the change in enthalpy is positive.**

Molecule | Enthalpy(KJ/mol) |

Fe | 0 |

H_{2}SO_{4} | -814 |

FeSO_{4} | -924.66 |

H_{2} | +242 |

**Enthalpy of Reactants**

**and Products**

## 9. Is H_{2}SO_{4} + Fe a buffer solution?

**The reaction between ****H _{2}SO_{4}**

**+ Fe gives a buffer solution of FeSO**

_{4}and H_{2}and they can control the pH of the reaction.## 10. Is H_{2}SO_{4} + Fe a complete reaction?

**The reaction ****H _{2}SO_{4}**

**+ Fe is the complete reaction because it gives one complete product FeSO**

_{4}along with H_{2}gas. The reaction takes need some time to complete until all the reactants completely reacted the products are not formed.**11. **Is H_{2}SO_{4} + Fe an exothermic or endothermic reaction?

**The reaction ****H _{2}SO_{4}**

**+ Fe is endothermic in terms of thermodynamics first law. So, the reaction takes more energy and temperature from the surroundings which help to complete the reaction, Where δH is always positive.**

## 12. Is H_{2}SO_{4} + Fe a redox reaction?

**H _{2}SO_{4} + Fe reaction is a **

**redox reaction**

**because in this reaction many elements get reduced and oxidized as hydrogen gets reduced and Fe gets oxidized.**

## 13. Is H_{2}SO_{4} + Fe a precipitation reaction

**The reaction H _{2}SO_{4} + Fe is a precipitation reaction because FeSO_{4} gets precipitated in the solution and is not soluble in the reaction mixture.**

## 14. Is H_{2}SO_{4} + Fe reversible or irreversible reaction?

**The reaction between H _{2}SO_{4}+ Fe is irreversible because we get H_{2} gas as a product. When gas is formed during the reaction the entropy of the reaction increases and the equilibrium of the reaction shifts towards the right-hand side only.**

## 15. Is H_{2}SO_{4} + Fe displacement reaction?

**The reaction between H _{2}SO_{4}+ Fe is an example **

**single displacement**

**reaction because in the above reaction Fe**

^{2+}displaced H^{+}in H_{2}SO_{4}only and H_{2}gas becomes free from the reaction.#### Conclusion

H_{2}SO_{4} and Fe reaction mainly gives us ferrous sulfide along with hydrogen gas so it is a commercially important reaction for the production of hydrogen gas. Also, the quantitative analysis of the H_{2}SO_{4} and Fe gives the amount of iron as well as sulfate in the respective sample.

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