Question
Download Solution PDFWhile testing for COD of sewage, organic matter is oxidised by K2Cr2O7 in the presence of
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Chemical Oxygen Demand (COD)
Chemical Oxygen Demand (COD) is a test that measures the amount of oxygen required to chemically oxidize the organic material and inorganic nutrients, such as Ammonia or Nitrate, present in water.
The COD test uses potassium dichromate (K2Cr2O7) in presence of concentrated sulfuric acid (H2SO4) solution that oxidizes both organic (predominate) and inorganic substances in a waste water sample.
The regents of COD test are
- Standard potassium dichromate(K2Cr2O7) solution (.25N)
- Concentrated sulfuric acid (H2SO4)
- Standard Ferrous ammonium sulphate titrant
- Ferroin indicator solution
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