H_{2}SO_{3} is an inorganic weak acid. The molecule of H_{2}SO_{3} can found in gas phase. BaO is a strong base. Let us try to understand some features of the reaction between H_{2}SO_{3} and BaO.

**H _{2}SO_{3} is a colorless substance with odor of sulphur. H_{2}SO_{3} is a white solid with corrosive property. BaO is also known as baria and it is a hygroscopic non-flammable compound. Generally BaO is used as drying agent in various chemical reactions.**

In this article, we will try to study about some frequently asked questions about the H_{2}SO_{3} and BaO reaction like the nature of the reaction, the product of the reaction, enthalpy, intermolecular forces etc.

**What is the product of H**_{2}SO_{3} + BaO?

_{2}SO

_{3}+ BaO?

**Barium sulfite (BaSO _{3}) and water (H_{2}O) are the products of the reaction between sulfurous acid (H_{2}SO_{3}) and barium oxide (BaO).**

**H _{2}SO_{3} + BaO = BaSO_{3} + H_{2}O**

**What type of reaction is H**_{2}SO_{3} + BaO?

_{2}SO

_{3}+ BaO?

**The H _{2}SO_{3} + BaO reaction is an example of neutralization reaction between weak acid and strong base. H_{2}SO_{3} is a weak acid and BaO is a strong base.**

**How to balance H**_{2}SO_{3} + BaO?

_{2}SO

_{3}+ BaO?

**The number of individual atoms (H, S, O, Ba) in the reactants and products should be the same in a balanced chemical equation. To get the balanced equation we have to follow some steps.**

**Here, it is found that four individual elements are present. Hence, in the first step, each molecule is labeled as A, C, D, and E.****Now, the reaction looks like this, A****H**_{2}SO_{3}+ C BaO = D BaSO_{3}+ E H_{2}O**All the same elements’ coefficients are rearranged by their stoichiometric proportion, and we get,****H = 2A + 0C = 0D + 2E, S = 1A + 0C= 1D + 0E, O = 3A + 1C = 3D + 1E, Ba = 0A + 1C = 1D + 0E.****Then by calculating the coefficient and variables by the Gaussian elimination process, we get the required values of A, C, D, and E.****It is found as,****A = 1, C = 1, D = 1, and E = 1.****Now, it is found that the number of moles of each element is both sides is equal.**

Symbol of Elements | Moles in reactant side | Moles in product side |
---|---|---|

H | 2 | 2 |

S | 1 | 1 |

O | 3 | 3 |

Ba | 1 | 1 |

**Moles of elements in reactant and product side**

**Hence, the overall balanced equation will be****H**_{2}SO_{3}+ BaO = BaSO_{3}+ H_{2}O

**H**_{2}SO_{3} + BaO titration

_{2}SO

_{3}+ BaO titration

**The strength of H _{2}SO_{3} can be determined by performing titration between a weak acid and strong base.**

**Apparatus used**

**Burette, 20 ml pipette, conical flask, burette stand, beakers, measuring cylinder, measuring flask, and funnel.**

**Titre and titrant**

**In H _{2}SO_{3} + BaO titration reaction, H_{2}SO_{3} is the titre and BaO is the titrant.**

**Indicator**

**Phenolpthalein is used as the indicator to detect the end point in this acid base neutralization reaction.**

**Procedure**

**Standardized solution of BaO is taken in the burette.****20 ml of H**_{2}SO_{3}of unknown strength is taken in a conical flask by using 20 ml pipette.**1-3 drops of Phenolpthalein indicator is added to acid in the conical flask.****From burette BaO was added dropwise into the conical flask until the pink colour is observed at the endpoint.****This process was repeated at least 3-4 times to get accurate reading.****The strength of H**_{2}SO_{3}is calculated by using the formula, N_{1}V_{1 }= N_{2}V_{2.}

**H**_{2}SO_{3} + BaO net ionic equation

_{2}SO

_{3}+ BaO net ionic equation

**The H _{2}SO_{3} + BaO reaction has the following kind of net ionic equation,**

**H ^{+} +HSO_{3}^{–} + Ba^{2+} + O^{2-} = Ba^{2+} + SO_{3}^{2-} + H^{+} +OH^{–}**

**H**_{2}SO_{3}is dissociated into H^{+}and HSO_{3}^{–}ions.**BaO dissociates into Ba**^{2+}+ O^{2-}ions.**BaSO**_{3}dissociates into Ba^{2+}and SO_{3}^{2-}ions.**H**_{2}O dissociates into H^{+}and OH^{–}ions.**Hence, the net ionic equation of H**_{2}SO_{3}+ BaO is H^{+}+HSO_{3}^{–}+ Ba^{2+}+ O^{2-}= Ba^{2+}+ SO_{3}^{2-}+ H^{+}+OH^{–}

**H**_{2}SO_{3} + BaO conjugated pairs

_{2}SO

_{3}+ BaO conjugated pairs

**The H _{2}SO_{3} + BaO has the following net conjugate pairs**

**The conjugate base of H**_{2}SO_{3}is HSO_{3}^{–}(by donating a proton).**The conjugate acid of BaO is Ba**^{2+}(according to Lewis concept).**The conjugate acid of H**_{2}O is H_{3}O^{+.}

**H**_{2}SO_{3} + BaO intermolecular forces

_{2}SO

_{3}+ BaO intermolecular forces

**H _{2}SO_{3} + BaO has the following intermolecular forces,**

**H**_{2}SO_{3}has electrostatic force of attraction between protons and sulphite ions.**BaO has covalent bonding.**

**H**_{2}SO_{3} + BaO reaction enthalpy

_{2}SO

_{3}+ BaO reaction enthalpy

**The standard reaction enthalpy of the reaction between H _{2}SO_{3} + BaO is -286349.39 kJ/mol, which is a negative value.**

Molecule | Enthalpy (of formation) kJ/mol |
---|---|

H_{2}SO_{3} | 52.89 |

BaO | -553.5 |

BaSO_{3} | -1030 |

H_{2}O | -285820 |

**Enthalpy of formation of molecules**

**Enthalpy change = (sum of enthalpy of formation of products) – (sum of enthalpy of formation of reactants) = [-1030 + (-) 285820] – [52.89 + (-) 553.50] = – 286349.39 kJ/mol.**

**Is H**_{2}SO_{3} + BaO a buffer solution?

_{2}SO

_{3}+ BaO a buffer solution?

**The H _{2}SO_{3} + BaO solution is not a buffer solution because H_{2}SO_{3} is a weak acid but BaO is not the conjugate base of that acid.**

**Is H**_{2}SO_{3} + BaO a complete reaction?

_{2}SO

_{3}+ BaO a complete reaction?

**The H _{2}SO_{3} + BaO reaction is the complete reaction as the products of the reaction, BaSO_{3 }and H_{2}O both are stable substances.**

**Is H**_{2}SO_{3} + BaO an exothermic or endothermic reaction?

_{2}SO

_{3}+ BaO an exothermic or endothermic reaction?

**The H _{2}SO_{3} + BaO reaction is exothermic as a negative enthalpy change value is obtained, and when these two elements react with each other, heat is released.**

**Is H**_{2}SO_{3} + BaO a redox reaction?

_{2}SO

_{3}+ BaO a redox reaction?

**The H _{2}SO_{3} + BaOreaction is not a redox reaction as the oxidation states of the elements (Ba, S, H) not change during the reaction.**

**Is H**_{2}SO_{3} + BaO a precipitation reaction?

_{2}SO

_{3}+ BaO a precipitation reaction?

**The H _{2}SO_{3} + BaO reaction is not a precipitation reaction because though BaSO_{3} is slightly soluble in water, no precipitate is formed during this reaction.**

**Is H**_{2}SO_{3} + BaO reversible or irreversible?

_{2}SO

_{3}+ BaO reversible or irreversible?

**The H _{2}SO_{3} + BaO reaction is irreversible because in this reaction the products, BaSO_{3} and H_{2}O, do not convert back to the reactants.**

**Is H**_{2}SO_{3} + BaO a displacement reaction?

_{2}SO

_{3}+ BaO a displacement reaction?

**The H _{2}SO_{3} + BaO reaction is a double displacement reaction as the ions of the reactants,H_{2}SO_{3} and BaO are swapped and produce new compounds as products.**

**Conclusion:**

The reaction of H_{2}SO_{3} with BaO is neutralization reaction which is characterized by the formation of a salt and water. H_{2}SO_{3} is used in food, cosmetic industries. BaSO_{3 }molecule has both ionic and covalent bond.