15 Facts on H2SO4 + SO3: What, How To Balance & FAQs

A mist of oleum is created when H2SO4 and SO3 through in a double displacement reaction. Let us examine some information about the reactions between H2SO4 and SO3.

Sulfuric acid(H2SO4) has a molecular mass of 98.07 g/mol. The components hydrogen, oxygen, and sulphur make up sulfuric acid, also known by its chemical formula H2SO4. Different chemical species and Crystal structures can be found in Sulphur trioxide (SO3) in its many different forms.

Sulfur trioxide(SO3) and water combine to generate sulfuric acid(H2SO4). Let us study the facts and reaction between H2SO4 + SO3 in more detail in the below section.

What is the product of H2SO4 and SO3?

The formation of Oleum/pyrosulfuric acid(H2S2O7)/Disulfuric acid takes place when Sulfuric acid(H2SO4) and Sulphur trioxide(SO3) react/combined. Oleum is a mist of small droplets to develop from the Sulfuric acid and the reaction is as follows:

H2SO4(l) + SO3(g) → H2S2O7(l)

What type of reaction is H2SO4 + SO3?

H2SO4 + SO3 is a synthesis or direct combination reaction because of the ion motions, that produce Sulfuric acid when it combines with water.

H2SO4 + SO3 → H2S2O7

H2S2O7(l) + H2O(l) → 2H2SO4(l)

How to balance H2SO4 + SO3?

This reaction between H2SO4 + SO3 is already balanced,

  • Write a Balanced equation: H2SO4 + SO3 → H2S2O7
  • The number of molecules from the elements 2H, 2S, and 7O are present on the reactant side, which means that the reaction between H2SO4 and SO3 is already in equilibrium. 
  • The product side contains atoms of 2S, 7O, and 2H.
  • The Gauss elimination method is used to determine all of the coefficients and variables since the 1:1:1 coefficient is the result.
  • A Balanced chemical equation: H2SO4 + SO3 → H2S2O7

H2SO4 + SO3 titration

The Barium-thorin titration method can be used to titrate between H2SO4 and SO3.

Apparatus Required

It is necessary to have Pipettes, Volumetric(10-ml, 100-ml), Burettes(50-ml), Erlenmeyer flasks(250 ml), Graduated cylinders(100-ml), dropping bottles, glass rods, funnels, and burette stands.

Indicator

The barium-thorin indicator is used during the titration between the H2SO4 and SO3 solution.

Procedure

  • Shake the bottle containing the filter and isopropanol solution
  • A sample aliquot should be taken after a few minutes if the filter separates.
  • A 100-ml portion of this solution should be pipetted into a 250-ml Erlenmeyer flask, followed by the addition of 2-4 drops of the barium-thorin indicator, followed by titration with 0.0100 N standard barium solution to achieve a pink endpoint.
  • Titration should be performed with a second aliquot of the sample, and titration values should be averaged. 
  • A duplicate titration must be within 1% of the first. 
  • The method should be repeated three times to obtain reliable results.
  • The required amount can be calculated using the formula N1V1 = N2V2.

H2SO4 + SO3 net ionic equation

The H2SO4 + SO3 have the following net Ionic equation,

2H+(l) + SO42-(l) + SO3(g) → 2H+(l) + S2O7(l)

  • The steps should be taken to reach the net ionic equation.
  • Create a balanced chemical equation and include a physical representation of the reactants’ and products’ states.
  • H2SO4(l) + SO3(g) → H2S2O7(l)
  • Pure substances and molecules are unable to dissociate into ions the way that salts, acids, and bases do.
  • The final net ionic equation is 
  • 2H+(l) + SO42-(l) + SO3(g) → 2H+(l) + HSO3+(l) + HSO4(l)

H2SO4 + SO3 conjugate pairs

The H2SO4 + SO3 has the following conjugate pairs,

  • H2SO4 is the conjugate base pair(HSO4).
h2so4 + so3
Conjugate acid-base pair

H2SO4 and SO3 intermolecular forces

The H2SO4 + SO3 has the following intermolecular forces,

H2SO4 + SO3 reaction enthalpy

H2SO4 + SO3 reaction has a Standard reaction enthalpy of -125kJ/mol. Reactants and products involved in the reaction have standard formation enthalpies

MoleculesReaction
enthalpy
(in kJ/mol)
H2SO4-814.4
SO3-191
H2S2O7-880
Enthalpy of reaction of molecules
  • ΔH⁰f(reaction) = ΣΔH⁰f(products) – ΣΔH⁰f(reactants)= -ve
  • H2SO4(l) + SO3(g)→ H2S2O7(l)
  • ΔH⁰f(reaction) = [ -880 – (-191 – 814.4) ] = -125kJ/mol.

Is H2SO4 + SO3 a buffer solution?

H2SO4 + SO3 reaction is not a Buffer solution because it comprises a strong acid, but rather a weak acid. Lewis acid status for SO3 is due to its ability to serve as an electron acceptor but its inability to withstand pH changes.

Is H2SO4 + SO3 a complete reaction?

The H2SO4 + SO3 reaction is complete because H2SO4 and SO3 produce fuming pyrosulfuric acid or oleum. Oleum(H2S2O7) reacted with water yields the desired Sulfuric acid concentration (H2SO4).

Is H2SO4 + SO3 an exothermic or endothermic reaction?

The H2SO4 + SO3 reaction is an Exothermic one because heat is generated when SO3 is bubbled through H2SO4 and sulphuric acid/oleum is the result. During the formation of the product, the value of the formation enthalpy is also negative.

Is H2SO4 + SO3 a redox reaction?

The H2SO4 + SO3 reaction is not a Redox reaction, because it is an addition reaction. Additionally, the oxidation states of the atoms do not change.

Is H2SO4 + SO3 a precipitation reaction?

The H2SO4 + SO3 reaction is not a Precipitation reaction since sulfuric acid is employed to absorb the SO3, and because SO3, or sulphur trioxide, is an acidic oxide, the reaction with water is very exothermic and exhibits a hydration reaction.

Is H2SO4 + SO3 reversible or irreversible reaction?

The H2SO4 + SO3 reaction is Reversible because the SO3 is absorbed by sulfuric acid during the reaction with water, resulting in the formation of oleum, which is then slowly added water to reform the sulfuric acid.

h2so4 + so3
 Reversible reaction

Is H2SO4 + SO3 displacement reaction?

The H2SO4 + SO3 reaction is a Double displacement reaction.

h2so4 + so3
 Double displacement reaction

Conclusion

H2SO4 + SO3 have finished their reaction, through a double displacement reaction. Oleum is produced when H2SO4  bubbles with SO3  and is then combined to create a highly reactive and strong odour liquid H2S2O7. The determination of H2SO4  and gaseous SO2 emissions from stationary sources.