Determination of Chemical Oxygen Demand
                    Excess dichromate is titrated by using ____________ as an indicator.
                  
                  
                  
                    Empirically, municipal waste water has a 5 day BOD of 
                  
                  
                  
                    The COD value will always be _____________ than the value of BOD for waste water.
                  
                  
                  
                    4. For untreated wate water BOD/COD ratio is 
                  
                  
                  
                    In which region chromic ion absorbs the light efficiently? 
                  
                  
                  