JEE Main · 2021 · 01 Sep 2021 · Shift 2 · Environmental Chemistry

Water sample is called cleanest on the basis of which one of the BOD values given below:

(A)3 ppm✓ Correct
(B)21 ppm
(C)11 ppm
(D)15 ppm

Answer: (A)

Solution

Biochemical oxygen demand measures the oxygen consumed in degrading organic matter, so a smaller BOD means less biodegradable pollution and cleaner water; clean water has a BOD below about

5 ppm

. The lowest listed value,

3 ppm

, marks the cleanest sample.

JEE Main · 2021 · 01 Sep 2021 · Shift 2 · Single correct option

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