Environmental Engineering

261.Which of the following is the most lethal water pollutant?

1. Phenol and cyanide
2. Chlorine
3. Alkalis
4. Suspended solids

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262.Which of the following is the most major constituents of air pollutants?

1. Oxides of sulphur
2. Oxides of nitrogen
3. Carbon monoxide
4. Hydrogen sulphide

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263.Which of the following is the most severe air pollutant?

1. Hydrocarbons
2. NOx
3. SO₂
4. CO

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264.Which of the following is the most widely used disinfectant in water treatment?

1. Chlorine
2. Irradiation of water by ultraviolet light
3. Cation exchanger
4. Coagulation

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265.Which of the following plants does not emit appreciable amount of SO₂ in atmosphere?

1. Thermal power plant
2. Petroleum refinery
3. Nitric acid plant
4. Sulphuric acid plant

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266.Which of the following pollutants is absent in the emissions from a fertiliser plant?

1. SO₂&SO₃
2. NO₂
3. NH₃
4. CO

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267.Which of the following pollutants, if present in atmosphere is detectable by its odour ?

1. CO
2. SO₂
3. NO₂
4. CO₂

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268.Which of the following processes is involved in the biochemical treatment of sewage effluents?

1. Oxidation
2. Reduction
3. Dehydration
4. Fermentation

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269.Which of the following radioactive wastes emits all α, β&γ rays and hence is the most hazardous of all radioactive emitters?

1. I-131
2. Sr-90
3. Au-198
4. Ra-226

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270.Which of the following sources is responsible for maximum air pollution?

1. Industrial chimney exhaust
2. Forest fire
3. Automobiles exhaust
4. Photochemical oxidation of organic matter

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