- 1(current)
Q. No.A student collected samples from two water bodies A and B in a metro city. The biochemical oxygen demand for 'A' is 3 ppm while for B is found to be 18 ppm. Which one of the following is true?
1. Both A and B are clean
2. Both A and B are polluted
3. A is clean but B is polluted
4. A is polluted but B is clean
Subtopic: Â Water Pollution - Biological Oxygen Demand |
 85%
Level 1: 80%+
NEET - 2022
Hints
Match List-I with List-II :
Choose the correct answer from the options given below:
| List-I | List-II |
| (a) Biochemical oxygen demand | (i) Oxidising mixture |
| (b) Photochemical smog | (ii) Polar stratospheric cloud |
| (c) Classical smog | (iii) Organic matter in water |
| (d) Ozone layer depletion | (iv) Reducing mixture |
| (a) | (b) | (c) | (d) | |
| 1. | (i) | (iv) | (ii) | (iii) |
| 2. | (iii) | (iv) | (i) | (ii) |
| 3. | (iii) | (i) | (iv) | (ii) |
| 4. | (iv) | (iii) | (ii) | (i) |
Subtopic: Â Air Pollution - Smog |Â Water Pollution - Biological Oxygen Demand |
 70%
Level 2: 60%+
NEET - 2022
Hints
Which one of the following statements is not true?
| 1. | Concentration of dissolved oxygen below 5 ppm is good for the growth of fish. |
| 2. | Clean water would have a BOD value of less than 5 ppm. |
| 3. | Oxides of sulphur, nitrogen, and carbon are the most widespread air pollutant. |
| 4. | pH of drinking water should be between 6.5-8.5. |
Subtopic: Â Water Pollution - Biological Oxygen Demand |
 67%
Level 2: 60%+
AIPMT - 2011
Hints
- 1(current)
Q. No.
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