Which of the following are used as disinfectants during water treatment? A.…
2023
Which of the following are used as disinfectants during water treatment?
A. Chlorine
B. Phosphorus
C. Ozone
D. Nitrogen
E. Ultraviolet Rays
Choose the most appropriate answer from the options given below:
Answer: C. A, C and E only — CONCEPTDisinfection is the treatment step that inactivates disease-causing microorganisms. Chemical oxidants such as chlorine and ozone damage essential…
- A.
A, B and C only
- B.
A, B and D only
- C.
A, C and E only
- D.
B, D and E only
Show answer & explanation
Correct answer: C
CONCEPT
Disinfection is the treatment step that inactivates disease-causing microorganisms. Chemical oxidants such as chlorine and ozone damage essential cellular components, while ultraviolet radiation disrupts microbial genetic material.
APPLICATION
Chlorine (A) and ozone (C) are chemical disinfectants. Ultraviolet rays (E) provide physical disinfection. Phosphorus (B) and nitrogen (D) are nutrients; excess amounts can contribute to eutrophication, but they are not water-treatment disinfectants.
CONTRAST
A, B and C includes phosphorus along with chlorine and ozone.
A, B and D includes the two nutrients phosphorus and nitrogen along with chlorine.
A, C and E groups chlorine, ozone and ultraviolet radiation, the three listed disinfection methods.
B, D and E includes the two nutrients phosphorus and nitrogen along with ultraviolet radiation.
CROSS-CHECK
A substance or process belongs in the selected set only if it directly inactivates microorganisms during treatment. Applying this test retains A, C and E.
Therefore, the appropriate combination is A, C and E only.