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.


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


Phenolphthalein is used as the indicator in this titration.


  • 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 H2SO (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 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 –

CompoundEnthalpy in KJ/mol
Enthalpy of reactants and products
  • Enthalpy of reaction (ΔHf) = Standard enthalpy of products – standard enthalpy of reactants
  • ΔHf = (-1407.21) – (-1234.55)
  • Thus, ΔHf = -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?

H2SO3BeO 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 H2SOto form BeSO3,  while O displaces sulphite ions to form water.

Screenshot 2023 01 06 232934
Double Displacement Reaction


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.