Question

Which of the following is true in clean water?

• A. BOD is low but DO is high
• B. Both BOD and DO are high
• C. BOD is high but DO is low
• D. Both BOD and DO are low

Answer 1

The correct option is A BOD is low but DO is high

BOD (biochemical oxygen demand) is defined as the amount of oxygen required by aerobic microorganisms to decompose the organic matter in a sample of water, such as that polluted by sewage. It is used as a measure of the degree of water pollution. Higher the BOD, more is the pollution of water.

DO (dissolved oxygen) is the amount of oxygen dissolved in a water sample. Higher the DO, lesser is the pollution of water.

In clean water, the concentration of BOD (biochemical oxygen demand) is low but the DO (dissolved oxygen) is high.