Converting Chlorine Dioxide to Free Residual Chlorine

Our water treatment facility used Chlorine Dioxide to disinfect the produced drinking water. The analysis results indicate concentrations of 0.2 mg/l of chlorine dioxide at the source. Can we analys residual chlorine in the distribution network? We dont have water quality standards for chlorine dioxide, only residual chlorine. Can I calculate the concentration of chlorine in the water from the concentration of chlorine dioxide?




Some chemistry, first add H2O2 and NaOH:



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> $\ce{2 ClO2 + H2O2 + 2 NaOH -> 2 NaClO2 + O2 (g) + 2 H2O }$
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Source: <https://chemiday.com/en/reaction/3-1-0-1114>


Continue adding H2O2, as:



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> $\ce{2 NaClO2 + 2 H2O2 -> 2 NaClO + 2 O2 (g) + 2 H2O }$
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> $\ce{2 NaClO + 2 H2O2 -> 2 NaCl + 2 O2 (g) + 2 H2O }$
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which implies a net reaction of:



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> $\ce{2 ClO2 + 5 H2O2 + 2 NaOH -> 2 NaCl + 5 O2 (g) + 6 H2O }$
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> 
> 


So, slowly add H2O2 until the bubbling ceases. Collect the volume of oxygen and convert to moles. Divide by 2.5 to determine moles of ClO2 and your chlorine therefrom.


Here is a related reference, [Titrimetric and photometric methods for determination of hypochlorite in commercial bleaches](https://www.tandfonline.com/doi/abs/10.1080/10934521003772295?scroll=top&needAccess=true&journalCode=lesa20), which cites the use of hydrogen peroxide and acidic permanganate.


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