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JEE Main · 2022 · 26 Jun 2022 · Shift 2 · Environmental Chemistry

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The measured BOD values for four different water samples (A-D) are as follows:
A = 3 ppm; B = 18 ppm; C = 21 ppm; D = 4 ppm. The water samples which can be called as highly polluted with organic wastes, are
  1. (A)A and B
  2. (B)A and D
  3. (C)B and C✓ Correct
  4. (D)B and D

Answer: (C)

Solution

BOD (Biochemical Oxygen Demand) is a measure of the amount of dissolved oxygen required by aerobic microorganisms to decompose organic matter in water.
  • Clean water: BOD < 5 ppm
  • Highly polluted water: BOD > 17 ppm

From the given data:
  • A = 3 ppm (clean)
  • B = 18 ppm (highly polluted)
  • C = 21 ppm (highly polluted)
  • D = 4 ppm (clean)

Therefore, samples B and C are highly polluted with organic wastes.

JEE Main · 2022 · 26 Jun 2022 · Shift 2 · Single correct option

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