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InterviewSolution
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Which of the following chemical reaction is the safest laboratory prepartion of chlorine dioxide?A. `2HCIO_(3)+2HCIrarr2CIO_(2)+Cl_(2)+2H_(2)O`B. `2NaCIO_(3)+SO_(2)+H_(2)SO_(4)rarr underset("of NaCl")overset("trace")(rarr)2CIO_(2)+2NaHSO_(4)`C. `2NaCIO_(3)+2(COOH)_(2)underset(90^(@)C)overset(H_(2)O)(rarr)2CIO_(2)+2CO_(2)+(COONa)_(2)+2H_(2)O`D. All of these |
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Answer» Correct Answer - 3 Even through pure chlorine dioxide is explosive , it is of major industrial importantance. About `10^(6)` tones is produced every year worldwide .It is difficult to determine the exact production total, because the gas is so harzardous that it is generally produced in comparatively small quantities at the sites where it is to be used. The safest laboratory preparation is from sodium chlorate and oxalic acid ,as the automatically dilutes the gas with `CO_(2)` `2NaCIO_(3)+2(COOH)_(2) underset(90^(@)C)overset(H_(2)O) rarr 2CIO_(2)+2CO_(2)+(COONa)_(2)+2H_(2)O` The gas is made commercially from `NaCIO_(3)` .Teh synethetic reaction involves th ereduction chlorine in the `+5(CIO_(3)^(-))` oxidation state by chlorine in the `-1 (CI^(-))` oxidation state in very acid condition to give chlorine in the `+4 (CIO_(2))` and `0(CI_(2))` oxidation states: `2HCIO_(3)+2HCl rarr 2CIO_(2)+CI_(2)+2H_(2)O` or `2CIO_(3)^(-)(aq.)+4H^(+)2CI^(-)(aq.)rarr2CIO_(2)(g)+CI_(2)(g)+2H_(2)O(l)` In North america ,sulphur dioxide is added to reduce (and remove) the dichlorine gas to chloride ion,the sulfur dioxide is simultaneously oxidized to sulphate: `SO_(2)(g)+2H_(2)O(l)rarrSO_(4)^(2-)(aq.)+4H^(+)(aq.)+2e^(-)` `CI_(2)(g)+2e^(-)rarr2CI^(-)(aq.)` However this process produced sodium sulfate waste. Thus a pure product is formed by using `SO_(2)` `2NaCIO_(3)+SO_(2)+H_(2)SO_(4) overset("trace")underset("of "NaCl) rarr2CIO_(2)+2NaHSO_(4)` Using `HCI` causes contaminating with `CI_(2)` but his may be unimportant or even useful for bleaching and sterilization. A German process separates the dichlorine from the chlorine dioxide then reacts the dichlorine with hydrogen gas to produce hydrochloine acid.The acid can then reused in the synthasis. |
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