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How is ozone estimated quantitatively? |
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Answer» Solution : Ozone oxidises potassium IODIDE to iodine as : `2KI + O_3 + H_2O to KOH + O_2+ I_2` The LIBERATED iodine may be titrated against a standard solution of sodium THIOSULPHATE. `I_2 + 2Na_2S_2O_3 to Na_2 S_4O_6 + 2NaI` Thus to estimate `O_3`quantitatively, ozone is allowed to react with known amount of excess potassium iodide solution buffered with a borate buffer (pH = 9.2). The liberated `I_2`is titrated against `Na_2S_2O_3`solution using starch as an INDICATOR. From this amount of ozone can be calculated. |
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