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Assertion: If BOD level of water in a re...

Assertion: If `BOD` level of water in a reservoir is less than 5 ppm it is highly pollution.
Reason: High biological oxygen demand means low activity of bacteria in water.

A

Both A and R are correct and R is the correct explanation of A

B

Both A and R are correct and R is not the correct explanation of A

C

Both A and R are not correct

D

A is not correct but R is correct

Text Solution

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The correct Answer is:
### Step-by-Step Solution: 1. **Understanding BOD**: - BOD stands for Biochemical Oxygen Demand. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. - A higher BOD indicates a higher level of organic pollution because more oxygen is required to break down the organic material. 2. **Analyzing the Assertion**: - The assertion states that if the BOD level of water in a reservoir is less than 5 ppm, it is highly polluted. - This statement is **false**. A BOD level of less than 5 ppm typically indicates that the water is clean and has low levels of organic waste. 3. **Analyzing the Reason**: - The reason states that high biological oxygen demand means low activity of bacteria in water. - This statement is **true**. A high BOD indicates that there is a lot of organic matter present, which requires more oxygen for decomposition. This can lead to low levels of dissolved oxygen, which can harm aquatic life. 4. **Conclusion**: - Since the assertion is false and the reason is true, the correct answer is that the assertion is incorrect, but the reason is correct. Therefore, the answer is option D.
### Step-by-Step Solution: 1. **Understanding BOD**: - BOD stands for Biochemical Oxygen Demand. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. - A higher BOD indicates a higher level of organic pollution because more oxygen is required to break down the organic material. 2. **Analyzing the Assertion**: - The assertion states that if the BOD level of water in a reservoir is less than 5 ppm, it is highly polluted. ...
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