Nitrite can be oxidized by potassium dichromate (K2Cr2O7) in acidic solution. 50.0 mL of waste water is titrated utilizing K2Cr2O7. It takes 17.87mL of 0.002587 M K2Cr2O7 to reach the endpoint. Define what is the nitrite concentration in the original waste water sample measured in mg /L?
Cr2O72- (aq) + NO2- (aq) ? Cr3+ (aq) + NO3- (aq) [unbalanced]