Q15 / 160 · AP EAMCET 2019 (20 Apr Shift 2) · Chemistry

Which one of the following statements is not correct?

  • A
    $\mathrm{NO}_2$ is a lung irritant
  • B
    The municipal sewage has $B O D$ value of $100-4000$ ppm
  • C
    Main source of CO is automobile exhaust fumes
  • Correct answer
    D
    COD is the measure of bacteria in water

Solution

In environmental chemistry, chemical oxygen demand (COD) is the total amount of oxygen, (in ppm) that would be consumed by pollutants in a given water sample measured solution. Thus, COD is useful in terms of water quality. Hence, option (d) is incorrect while the other given statements are correct. i.e. - Municipal sewage has BOD (Biological oxygen demand) value of $100-4000 \mathrm{ppm}$. - $\mathrm{NO}_2$ can causes irritation of eyes, noise even lungs. About $70 \%$ CO is mainly from automobiles exhaust fumes.

Hence, the correct answer is option: 'D'.

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