Select the incorrect statement. : Water is considered pure if it has BOD less than 5 ppm., In COD determination, the pollutants resistant to microbial oxidation are not oxidized by oxidizing agent like `K_2Cr_2O_7` , The lower the concentration of DO, the more polluted is the water sample, The tolerable limit of lead in drinking water is 50 ppb.

Options

A. Water is considered pure if it has BOD less than 5 ppm.
B. In COD determination, the pollutants resistant to microbial oxidation are not oxidized by oxidizing agent like `K_2Cr_2O_7`
C. The lower the concentration of DO, the more polluted is the water sample
D. The tolerable limit of lead in drinking water is 50 ppb.

Answer

B

Explanation

In COD determination the pollutants resistant to microbial oxidation are oxidized byoxidizing agent like `K_2Cr_2O_7`