The Chemistry Behind H2SO3 + BeO: 15 Facts You Should Know

Beryllium oxide is an inorganic oxide of beryllium with chemical formula BeO. Sulphurous acid (H₂SO₃) is a colorless mineral acid. Let us study the reaction between H₂SO₃ and BeO_.

BeO is a white crystalline acidic oxide found naturally in Bromellite mineral. It is the only amphoteric oxide among Group I and II metal oxides. BeO has excellent electrical insulating properties. H₂SO₃ is a corrosive, oily liquid and is an intermediate product in acid rain formation.

In this article, let us learn about various properties based on the reaction H₂SO₃ + BeO, like the product formed, the type of reaction, titration,  buffer solution, conjugate pairs etc.

What is the product of H₂SO₃ and BeO?

Beryllium sulphite (BeSO₃) and water (H₂O) are the products when beryllium oxide reacts with sulphurous acid.

BeO + H₂SO₃  –> BeSO₃ + H₂O

What type of reaction is H₂SO₃ + BeO?

H₂SO₃ + BeO is categorized as a neutralization reaction as the reaction produces sulphite salt and water.

How to balance H₂SO₃ + BeO?

The equation for the reaction H₂SO₄ + BeO is

H₂SO₄ + BeO –>  BeSO₃ + H₂O

The reaction is in a self-balanced state as both the sides of the reaction have an equivalent number of atoms of each of the four elements H, O, S, and Be.

H₂SO₃ + BeO  titration

BeO being an insoluble salt, is back-titrated with H₂SO₃ to determine its concentration by using the following procedure.

Apparatus

Burette, burette stand, volumetric flask, pipette, conical flask, and measuring cylinder.

Indicator

Phenolphthalein is used as the indicator in this titration.

Procedure

• In a conical flask, take a surplus amount of standardized solution of H₂SO₃, and dissolve BeO in it.
• Add 1-2 drops of phenolphthalein indicator.
• Titrate the excess amount of H₂SO₃  (left after reaction with BeO), with standard NaOH solution taken in the burette, until the colorless solution changes to light pink.
• Repeat the above procedure 3 times and record the average burette reading.
• Finally, the amount of unreacted H₂SO₃ can be calculated using the formula S₁V₁ = S₂V₂.
• The amount of H₂SO₃ that has reacted with BeO can be obtained by deducting the amount of unreacted H₂SO₃ from the total amount taken.
• The concentration of BeO can be determined from the amount of H₂SO₃ that has been consumed in the reaction.

H₂SO₃ + BeO  net ionic equation

The net ionic equation of H₂SO₃ + BeO cannot be calculated as the reaction solubility quotient is not known. BeO is a solid, while H₂SO₃ is a weak acid, so its aqueous form does not dissociate into ions. The dissociation of the products BeSO₃ and H₂O are limited as they exist in aqueous and liquid forms, respectively.

H₂SO₃ + BeO  conjugate pairs

In H₂SO₃ and BeO, the conjugate pairs are:

• H₂SO₃ and HSO₃^– (bisulphite anion) are the conjugate acid-base pairs.
• BeO does not have a conjugate pair as it is a metal oxide.

H₂SO₃ + BeO  intermolecular forces

The intermolecular forces existing between H₂SO₃ and BeO is as follows:

• In H₂SO₃, the hydrogen and sulphite ions are held by dipole-dipole interactions, Van der Waals forces, and London dispersion forces.

• In BeO, a strong electrostatic force of attraction is present as it is ionic in nature.

H₂SO₃ + BeO  reaction enthalpy

H₂SO₃ + BeO reaction enthalpy is -172.66 kJ/mol. This negative reaction enthalpy can be calculated by using the enthalpy of formation values as illustrated below –

Compound	Enthalpy in KJ/mol
H2SO3	-635.55
BeO	-599.00
BeSO3	-1121.38
H2O	-285.83

• Enthalpy of reaction (ΔH_f) = Standard enthalpy of products – standard enthalpy of reactants

• ΔH_f = (-1407.21) – (-1234.55)

• Thus, ΔH_f = -172.66 kJ/mol.

Is H₂SO₃ + BeO a buffer solution?

H₂SO₃ + BeO is an indirect buffer solution as the reaction mixture yields a weak acid and beryllium sulphite salt (which results from the reaction between a weak acid and BeO, an amphoteric oxide).

Is H₂SO₃ + BeO a complete reaction?

H₂SO₃ + BeO is a complete reaction, as the equilibrium in the neutralization reaction shifts towards the forward direction leading to the formation of salt and water.

Is H₂SO₃ + BeO an exothermic reaction?

H₂SO₃ + BeO is an exothermic reaction because heat is generated in the reaction as indicated by the negative value of the reaction enthalpy.

Is H₂SO₃ + BeO a redox reaction?

H₂SO₃ + BeO is not a redox reaction, as the oxidation states of each of the elements remains the same throughout the reaction.

Is H₂SO₃ + BeO a precipitation reaction?

The reaction of H₂SO₃ and BeO is not a precipitation reaction. Barium sulphite formed as the product is only sparingly soluble.

Is H₂SO₃ + BeO an irreversible reaction?

H₂SO₃ + BeO is an irreversible reaction because the products BeSO₃ and H₂O cannot revert back to starting materials.

Is H₂SO₃ + BeO a displacement reaction?

The reaction between H₂SO₃ + BeO is an example of a double displacement reaction, or salt metathesis reaction. In this reaction, Be displaces H from H₂SO₃  to form BeSO_3,  while O displaces sulphite ions to form water.

Conclusion

H₂SO₃ + BeO is an acid-base reaction between a weak acid and an amphoteric oxide. Sulphurous acid is a weak electrolyte and is moderately stable. The properties and uses of beryllium sulphite formed in this reaction are not widely known, as it quickly oxidizes to beryllium sulphate.