Why is BaSO4 insoluble in HNO3?
BaSO4 is insoluble in HNO3 (nitric acid) because of the nature of the chemical reaction that occurs between the two substances. To explain why BaSO4 is insoluble in HNO3, we need to understand the solubility rules and the possible reactions that can take place.
Solubility rules are guidelines that suggest whether a compound is likely to be soluble or insoluble in water or other solvents. According to the solubility rules, sulfates (SO4 2-) are generally soluble except when they are combined with certain cations. Barium (Ba2+) is one of those cations that forms an insoluble sulfate when combined with sulfate ions.
When BaSO4 is added to HNO3, a displacement reaction can occur. The nitrate ion (NO3-) in HNO3 can potentially replace the sulfate ion (SO4 2-) in BaSO4, resulting in the formation of barium nitrate (Ba(NO3)2) and a byproduct of H2SO4 (sulfuric acid). However, the reaction between BaSO4 and HNO3 is extremely slow and limited in extent, leading to the insolubility of BaSO4 in HNO3.
To confirm the insolubility of BaSO4 in HNO3, you can perform an experiment by adding a small amount of BaSO4 powder to a test tube containing HNO3. If BaSO4 is insoluble, you will observe that the BaSO4 particles do not dissolve in the HNO3 and eventually settle at the bottom of the test tube.
In summary, BaSO4 is insoluble in HNO3 due to the limited extent of the displacement reaction between BaSO4 and HNO3, according to the solubility rules and the specific properties of these substances.