Q84. Consider the following statements:
1. Absence of organic and inorganic wastes in water decreases the dissolved Oxygen (DO) content of the water.
2. The demand for O2 is directly related to increasing input of organic wastes and is expressed as biological oxygen demand of water.
3. BOD is limited to biodegradable materials only.
Which of the above statement(s) is/are correct?

(a) Only 1 and 2

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(b) Only 2

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(d) Only 3

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Solution

The correct option is C (c) Only 2 and 3
Presence of organic and inorganic wastes in water decreases the dissolved Oxygen (DO) content of the water.
The higher amounts of waste increases the rates of decomposition and O2 consumption, thereby decreases the DO content of water. The demand for O2 is directly related to increasing input of organic wastes and is expressed as biological oxygen demand (BOD) of water.
The higher value of BOD indicates low DO content of water. Since BOD is limited to biodegradable materials only. Therefore, it is not a reliable method of measuring pollution load in water.

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Similar questions

Q. Q. Consider the following statements

1. Water pollution by organic wastes is measured in terms of Biochemical Oxygen Demand.
2. BOD is the amount of dissolved oxygen needed by bacteria in decomposing the organic wastes present in water.
3. The higher value of BOD indicates a high level of Dissolved Oxygen content of water.

Which of the statements given above is/are correct?

Q. निम्नलिखित कथनों पर विचार कीजिए

1. जैविक कचरे द्वारा जल प्रदूषण को बायोकेमिकल ऑक्सीजन डिमांड (Biochemical Oxygen Demand-BOD) के संदर्भ में मापा जाता है।
2. BOD जल में मौजूद कार्बनिक कचरे को विघटित करने में बैक्टीरिया द्वारा आवश्यक घुलित ऑक्सीजन की मात्रा है।
3. BOD का उच्च मान जल में घुलित ऑक्सीजन के उच्च स्तर को इंगित करता है।

ऊपर दिए गए कथनों में से कौन सा सही है / हैं?

Q. Read the following statements (A-D) related to Biochemical Oxygen Demand (BOD) and identify the correct option stating true (T) and false (F).

A. Biochemical oxygen demand is defined as the amount of dissolved oxygen needed by microorganisms in decomposing the inorganic wastes.
B. Greater the BOD of waste water, the higher is the amount of organic matter present.
C. The BOD increases with time as organic matter gets decomposed.
D. Sewage water is treated till the BOD is reduced

The amount of O₂ required by bacteria in water to breakdown wastes into simple inorganic substances is called

Q32 Consider the following statements,

i) The chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water.

ii) Biochemical oxygen demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.

Which of the above statements is/are correct?

93. Consider the following statements,

1. Steam at 100°C and boiling water at 100°C contain same amount of heat.

2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water.

3. In an air-conditioner, heat is extracted from the room air at the evaporator coils and is rejected out at the condenser coils.

Which of these statements is/are correct?

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