Which one is bisulphite radical?
SO4^(2-) HSO4^(1-) HSO3^(1-) SO3^(2-)
Answers
Answer:
Disulfate Ion as an Intermediate to Sulfuric Acid in Acid Rain Formation
SULFUR DIOXIDE (SO2), WHICH IS produced from combustion of fossil fuels, can be oxidized to sulfuric acid in the atmosphere and contribute to acid rain formation. Many oxidation pathways can occur in the atmosphere (1), one of which is the oxidation of SO2 by O2 in aqueous droplets such as in fog, clouds, and rain. This oxidation reaction has been studied for almost a century and yet the oxidation mechanism is unclear. Rate laws and rate constants obtained for this reaction by previous investigators have been inconsistent because the reaction is very sensitive to many kinds of impurities; some of these impurities act as catalysts, while others are inhibitors at very low concentrations. Most of these kinetic studies were performed at atmospheric pressure by measuring the consumption rate of one of the reactants or the production rate of sulfate ion by conventional wet analytical methods. The concentrations of the other species were inferred from the stoichiometry of the reaction.
2HSO3- O2 2SO4(2-) 2H (1)
Unlike the approaches used by previous investigators, we have studied this reaction under high-pressure conditions with laser Raman spectroscopy (LRS) to monitor the dynamics of all known species involved during the course of the reaction. With this approach we have found that a mass balance of sulfur and oxygen cannot be achieved for the entire course of the reaction by just considering the known species. Subsequently, a previously undetected intermediate that is present in substantial quantity and relatively long-lived was discovered.
The high-pressure rapid-mixing flow system used in our study can be pressurized to 100 atm so that a sufficiently high dissolved oxygen concentration can be detected by LRS. In addition to dissolved oxygen, all of the other important species in the reaction system can be observed with LRS: SO2 (aq), HSO3-, SO3(2-), HSO4-, SO4(2-), S2O5(2-), and S2O6(2-). Sodium perchlorate was added to the reaction mixture as a reference so that quantitative measurements could be made.
Atmospheric water droplets are often very acidic. The pH of water droplets is 5.6 when in equilibrium with 0.03% CO2 in air. The dissolution of SO2 and NO(x) can further lower this value. Measurements of fog droplets and rain at many locations worldwide have yielded pH values less than 4 (2). Under acidic conditions HSO3- will be the dominant species from the dissolution of SO2 in aqueous solutions. Thus we performed most of the experiments in our study of the oxidation of HSO3- by O2 under conditions similar to these.