Question

Which of the following is/are estimated by titrating polluted water with potassium dichromate solution in acidic medium?

• A. I only
• B. II only
• C. II \& III only
• D. I, II, III

Hint:

- COD is measured using potassium dichromate in acidic medium.
- BOD and DO require different estimation methods.

Answer 1

The Correct Option is A

Step 1: Understanding the Estimation of Pollutants Chemical Oxygen Demand (COD) is a measure of the total amount of oxygen required to oxidize both organic and inorganic pollutants in water. It is determined by titrating the sample with potassium dichromate in acidic medium.
Step 2: Why Only COD? - COD estimation involves potassium dichromate in an acidic medium.
- Biochemical Oxygen Demand (BOD) measures oxygen consumption by microorganisms, typically determined using a different method.
- Dissolved Oxygen (DO) is estimated using the Winkler’s method, not potassium dichromate. Thus, only COD (I) is estimated using potassium dichromate titration.