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Home » Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted. Reason (R): High biological oxygen demand means a low activity of bacteria in water. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct. (iv) A is not correct but R is correct.
Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted. Reason (R): High biological oxygen demand means a low activity of bacteria in water. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct. (iv) A is not correct but R is correct.
CBSE | Chemistry | Class 11 | Environmental Chemistry | ncert exemplar
Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted. Reason (R): High biological oxygen demand means a low activity of bacteria in water. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct. (iv) A is not correct but R is correct.

Option (iii) is the answer.

i

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