Dissolved oxygen (DO) should not be less than _____________ mg/L of water. (a) 14 (b) 3 (c) 5 (d) 2

Dissolved oxygen (DO) should not be less than _____________ mg/L of water. (a) 14 (b) 3 (c) 5 (d) 2
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If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Description : If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l

Last Answer : ANS: D

With regard to standard of quality of drinking water as laid down by Indian Railway , the requirement (desirable) limit of total dissolved solids should not be more than---------- mg/l a)200 b) 300 c) 400 d) 500*

Description : With regard to standard of quality of drinking water as laid down by Indian Railway , the requirement (desirable) limit of total dissolved solids should not be more than---------- mg/l a)200 b) 300 c) 400

Last Answer : d) 500*

On nephelometry turbidity unit (NTU) is equal to the turbidity produced by (a) 1 mg SiO2 dissolved in 1 l of distilled water with the test being run according to absorption principle (b) 1 mg SiO2 dissolved in 1 l of distilled water with the test being run according t scattering principle (c) 1 mg Formazin dissolved in 1 l of distilled water with the test being run according to absorption principle (d) 1 mg Formazin dissolved in 1 l o f distilled water with the test being run according to scattering principle.

Description : On nephelometry turbidity unit (NTU) is equal to the turbidity produced by (a) 1 mg SiO2 dissolved in 1 l of distilled water with the test being run according to absorption principle (b) 1 ... Formazin dissolved in 1 l o f distilled water with the test being run according to scattering principle.

Last Answer : (d) 1 mg Formazin dissolved in 1 l o f distilled water with the test being run according to scattering principle.

The concentration of Total Dissolved Solids (TDS) in drinking water should not exceed (A) 500 mg/L (B) 400 mg/L (C) 300 mg/L (D) 200 mg/L

Description : The concentration of Total Dissolved Solids (TDS) in drinking water should not exceed (A) 500 mg/L (B) 400 mg/L (C) 300 mg/L (D) 200 mg/L

Last Answer : (A) 500 mg/L

Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Description : Lagoons used for purification of polluted water (A) Are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds (B) Use micro-organisms/bacteria in presence of dissolved oxygen (C) Gives an ... 1 mg/litre and BOD = 3.8 mg/litre (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organisms is - (1) 4 - 6 (2) 2 - 4 (3) 8 - 10 (4) 12 - 16

Description : The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organisms is - (1) 4 - 6 (2) 2 - 4 (3) 8 - 10 (4) 12 - 16

Last Answer : (1) 4 - 6 Explanation: Oxygen is one of several dissolved gases important to aquatic systems. Dissolved oxygen is necessary to maintain aerobic conditions in surface waters and is ... approach saturation - that concentration which is in equilibrium with the partial pressure of atmospheric oxygen.

The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organisms is : (1) 4 – 6 (2) 2 – 4 (3) 8 – 10 (4) 12 – 16

Description : The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organisms is : (1) 4 – 6 (2) 2 – 4 (3) 8 – 10 (4) 12 – 16

Last Answer :  4 – 6

For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than __________ ppm. (A) 10000 (B) 5 (C) 500 (D) 1000

Description : For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than __________ ppm. (A) 10000 (B) 5 (C) 500 (D) 1000

Last Answer : (B) 5

If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 250 mg/l

Description : If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 250 mg/l

Last Answer : ANS: D

Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by (A) Chlorination (B) Treating in biological oxygen pond (C) Chemical coagulation (D) None of these

Description : Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by (A) Chlorination (B) Treating in biological oxygen pond (C) Chemical coagulation (D) None of these

Last Answer : (B) Treating in biological oxygen pond

Dissolved oxygen content in river water is around __________ ppm. (A) 5 (B) 100 (C) 250 (D) 500

Description : Dissolved oxygen content in river water is around __________ ppm. (A) 5 (B) 100 (C) 250 (D) 500

Last Answer : (A) 5

What is the minimum amount of dissolved oxygen in pond water ?

Description : What is the minimum amount of dissolved oxygen in pond water ?

Last Answer : Dissolved oxygen in pond water at least 5 m. Need to be grams / liter.

With the rise of water temperature, dissolved oxygen:

Description : With the rise of water temperature, dissolved oxygen:

Last Answer : With the rise of water temperature, dissolved oxygen: A. Remains unchanged when algal bloom occurs ... D. Is more available to aquatic organisms.

state the processes responsible for the reduction of dissolved oxygen in water

Description : state the processes responsible for the reduction of dissolved oxygen in water

Last Answer : state the processes responsible for the reduction of dissolved oxygen in water

What environment has the greater concentration of dissolved oxygen warm water or cool water?

Description : What environment has the greater concentration of dissolved oxygen warm water or cool water?

Last Answer : You can't tell just from the temp - cool water is capable ofdissolving more oxygen ... but that doesn't mean that it will (ordoes).

(2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for determining this amount. This is not a precise quantitative test, although it is widely used as an indication of the organic quality of water.

Description : (2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to ... quantitative test, although it is widely used as an indication of the organic quality of water.

Last Answer : The addition of gypsum to port-land cement helps in : (1) increasing the strength of cement (2) rapid setting of cement (3) preventing rapid setting of cement (4) reduction in the cost of cement

The factor responsible for purification of sewage in river is A. Hydrology B. Dissolved oxygen in water C. Temperature D. All the above

Description : The factor responsible for purification of sewage in river is A. Hydrology B. Dissolved oxygen in water C. Temperature D. All the above

Last Answer : ANS: D

Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above

Description : Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated ... river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above

Last Answer : ANS: D

Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents

Description : Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents

Last Answer : ANS: C

Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above

Description : Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above

Last Answer : ANS: D

Heavy water used in the nuclear reactors to slow down the speed of neutrons is (A) Highly purified water (B) A compound of oxygen and deuterium (C) Water having dissolved salts of heavy metals (D) None of these

Description : Heavy water used in the nuclear reactors to slow down the speed of neutrons is (A) Highly purified water (B) A compound of oxygen and deuterium (C) Water having dissolved salts of heavy metals (D) None of these

Last Answer : (B) A compound of oxygen and deuterium

Lead pipes are not safe for carrying drinking water because water containing dissolved oxygen attacks lead thereby forming poisonous Pb (OH)2 . Lead pipes are readily corroded by (A) Dilute HCI (B) Acetic acid (C) Concentrated H2SO4 (D) None of these

Description : Lead pipes are not safe for carrying drinking water because water containing dissolved oxygen attacks lead thereby forming poisonous Pb (OH)2 . Lead pipes are readily corroded by (A) Dilute HCI (B) Acetic acid (C) Concentrated H2SO4 (D) None of these

Last Answer : (B) Acetic acid

Lead pipes are not safe for carrying drinking water, because water, containing dissolved oxygen attacks lead thereby forming poisonous Pb(OH)2 . Lead pipes are readily corroded by (A) Dilute HCl (B) Acetic acid (C) Concentrated H2SO4 (D) None of these

Description : Lead pipes are not safe for carrying drinking water, because water, containing dissolved oxygen attacks lead thereby forming poisonous Pb(OH)2 . Lead pipes are readily corroded by (A) Dilute HCl (B) Acetic acid (C) Concentrated H2SO4 (D) None of these

Last Answer : (B) Acetic acid

When domestic sewage mixes with river water (a) small animals like rats will die after drinking river water (b) the increased microbial activity releases micronutrients such as iron (c) the increased microbial activity uses up dissolved oxygen (d) the river water is still suitable for drinking as impurities are only about 0.1%.

Description : When domestic sewage mixes with river water (a) small animals like rats will die after drinking  river water (b) the increased microbial activity releases  micronutrients such as iron (c) the increased ... (d) the river water is still suitable for drinking as  impurities are only about 0.1%.

Last Answer : (c) the increased microbial activity uses up  dissolved oxygen

How dissolved oxygen control is achieved in feed water system?

Description : How dissolved oxygen control is achieved in feed water system?

Last Answer : Hydrazine is added to feed water system to control dissolved oxygen.  

Tri-sodium phosphate is used in boiler water treatment to reduce (A) Turbidity (B) Caustic embrittlement (C) Suspended silica (D) Dissolved oxygen

Description : Tri-sodium phosphate is used in boiler water treatment to reduce (A) Turbidity (B) Caustic embrittlement (C) Suspended silica (D) Dissolved oxygen

Last Answer : (B) Caustic embrittlement

Which of the following is the most detrimental for water used in high pressure boiler? (A) Silica (B) Turbidity (C) Phenol(D) Dissolved oxygen

Description : Which of the following is the most detrimental for water used in high pressure boiler? (A) Silica (B) Turbidity (C) Phenol (D) Dissolved oxygen

Last Answer : (A) Silica

Pick out the wrong statement. (A) Caustic embrittlement of boiler's metallic parts is caused by highconcentration of caustic soda in boiler feed water(B) Cooling and freezing of water kills the bacteria present in it(C) With increasing boiler operating pressure of steam, the maximumallowable concentration of silica in feed water goes on decreasing(D) Dissolved oxygen content in high pressure boiler feed water should benil

Description : Pick out the wrong statement. (A) Caustic embrittlement of boiler's metallic parts is caused by highconcentration of caustic soda in boiler feed water (B) Cooling and freezing of water kills the ... goes on decreasing (D) Dissolved oxygen content in high pressure boiler feed water should be nil

Last Answer : (B) Cooling and freezing of water kills the bacteria present in it

. Presence of iron and manganese in water causes (A) Reduction in its dissolved oxygen content (B) Discoloration of bathroom fixtures (C) Temporary hardness (D) None of these

Description : . Presence of iron and manganese in water causes (A) Reduction in its dissolved oxygen content (B) Discoloration of bathroom fixtures (C) Temporary hardness (D) None of these

Last Answer : (B) Discoloration of bathroom fixtures

Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by (A) Natural aeration of water stream (B) Photosynthetic action of algae (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by (A) Natural aeration of water stream (B) Photosynthetic action of algae (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Deaeration of high pressure boiler feed water is done to reduce (A) Foaming from boilers (B) Its dissolved oxygen content (C) Its silica content (D) Caustic embrittlement

Description : Deaeration of high pressure boiler feed water is done to reduce (A) Foaming from boilers (B) Its dissolved oxygen content (C) Its silica content (D) Caustic embrittlement

Last Answer : (B) Its dissolved oxygen content

The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water. (A) Dissolved oxygen content (B) Biological oxygen demand (C) Vapor pressure (D) All (A), (B) and (C)

Description : The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water. (A) Dissolved oxygen content (B) Biological oxygen demand (C) Vapor pressure (D) All (A), (B) and (C)

Last Answer : (A) Dissolved oxygen content

Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes (A) Fire hazards (B) Explosion hazards (C) Persistent foam (D) Depletion of dissolved oxygen

Description : Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes (A) Fire hazards (B) Explosion hazards (C) Persistent foam (D) Depletion of dissolved oxygen

Last Answer : (C) Persistent foam

Use of water having dissolved oxygen in boilers promotes (A) Corrosion (B) Sequestration (C) Scale formation(D) None of these

Description : Use of water having dissolved oxygen in boilers promotes (A) Corrosion (B) Sequestration (C) Scale formation (D) None of these

Last Answer : (A) Corrosion

Hydrazine is used in water treatment for the removal of (A) Colloidal impurities (B) Dissolved oxygen (C) Turbidity (D) Chlorinous taste

Description : Hydrazine is used in water treatment for the removal of (A) Colloidal impurities (B) Dissolved oxygen (C) Turbidity (D) Chlorinous taste

Last Answer : (B) Dissolved oxygen

Which of the following impurities in feed water for high pressure boiler is the most detrimental? (A) Silica (B) Dissolved oxygen (C) Suspended salt (D) Dissolved salt

Description : Which of the following impurities in feed water for high pressure boiler is the most detrimental? (A) Silica (B) Dissolved oxygen (C) Suspended salt (D) Dissolved salt

Last Answer : (A) Silica

Chlorination of water does not remove (A) Ammonia content (B) B.O.D. (C) Organic matter content (D) Dissolved oxygen

Description : Chlorination of water does not remove (A) Ammonia content (B) B.O.D. (C) Organic matter content (D) Dissolved oxygen

Last Answer : (D) Dissolved oxygen

The best guide to judge the general quality of water is the measurement of its (A) pH value (B) Electrical conductivity (C) Turbidity (D) Dissolved oxygen content

Description : The best guide to judge the general quality of water is the measurement of its (A) pH value (B) Electrical conductivity (C) Turbidity (D) Dissolved oxygen content

Last Answer : (B) Electrical conductivity

Which of the following is not a feature of potable water? a) It must be clean, colourless and odourless. b) It must be free from bacteria c) It must have excessive sodium ,calcium and magnesium d) It must contain dissolved oxygen and carbon dioxide

Description : Which of the following is not a feature of potable water? a) It must be clean, colourless and odourless. b) It must be free from bacteria c) It must have excessive sodium ,calcium and magnesium d) It must contain dissolved oxygen and carbon dioxide

Last Answer : c) It must have excessive sodium ,calcium and magnesium

Which of the following parameters is not used as a pollution indicator in water? (A) Total dissolved solids (B) Coliform count (C) Dissolved oxygen (D) Density

Description : Which of the following parameters is not used as a pollution indicator in water? (A) Total dissolved solids (B) Coliform count (C) Dissolved oxygen (D) Density

Last Answer : Answer: D

For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm

Description : For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm

Last Answer : ANS: B

What is true about RBCs in humans? (a) They carry about 20-25 percent of CO2. (b) They transport 99.5 percent of O2. (c) They transport about 80 percent oxygen only and the rest 20 percent of it is transported in dissolved state in blood plasma. (d) They do not carry CO2 at all.

Description : What is true about RBCs in humans? (a) They carry about 20-25 percent of CO2. (b) They transport 99.5 percent of O2. (c) They transport about 80 percent oxygen only and the rest 20 percent of it is transported in dissolved state in blood plasma. (d) They do not carry CO2 at all.

Last Answer : (a) They carry about 20-25 percent of CO2.

Which sensors are used to identify dissolved oxygen?

Description : Which sensors are used to identify dissolved oxygen?

Last Answer : Dissolved oxygen is the amount of free oxygen in water or any other liquid. Sensors on the other hand are devices/equipment used to measure the amount of the dissolved oxygen in an aqueous ... inbuilt barometer thus making it quick and accurate unlike YSI 55 which doesn't have inner barometer.

What take oxygen during the lung respiration and oxygen gas is dissolved in the blood stream?

Description : What take oxygen during the lung respiration and oxygen gas is dissolved in the blood stream?

Last Answer : What is the answer ?

Where is dissolved oxygen likely to be lowest?

Description : Where is dissolved oxygen likely to be lowest?

Last Answer : Need answer

Commercial nitric acid is coloured because it contains dissolved – (1) Oxygen (2) Nitrous oxide (3) Nitrogen dioxide (4) Coloured impurities

Description : Commercial nitric acid is coloured because it contains dissolved – (1) Oxygen (2) Nitrous oxide (3) Nitrogen dioxide (4) Coloured impurities

Last Answer : (3) Nitrogen dioxide Explanation: Commercial nitric acid has a brown colour due to dissolved NO2. The procedure of bubbling dry air through warm commercial nitric acid, is to drive away the dissolved nitrogen dioxide so that the acid becomes colourless.

The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known A. Bio-Chemical Oxygen Demand (B.O.D.) B. Dissolved Oxygen (D.O.) C. Chemical Oxygen Demand (C.O.D.) D. None of these

Description : The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known A. Bio-Chemical Oxygen Demand (B.O.D.) B. Dissolved Oxygen (D.O.) C. Chemical Oxygen Demand (C.O.D.) D. None of these

Last Answer : ANS: B

The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs) (c) when treated in STPs does not really require the aeration step as the sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Description : The domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in ... sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.

Last Answer : (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)

Which of the following actions have to be avoided to prevent the depletion of DO (dissolved oxygen) in aquaculture? [a] Over-aerating, over-warming, over-harvesting [b] Over-seining, over-planting, over-medicating [c] Over-feeding, over-stocking, over-fertilizing [d] None of these [e] All of the above

Description : Which of the following actions have to be avoided to prevent the depletion of DO (dissolved oxygen) in aquaculture? [a] Over-aerating, over-warming, over-harvesting [b] Over-seining, over-planting, over- ... c] Over-feeding, over-stocking, over-fertilizing [d] None of these [e] All of the above

Last Answer : [c] Over-feeding, over-stocking, over-fertilizing

Which one of the following statements is wrong? (a) Algae increase the level of dissolved oxygen in the immediate environment. (b) Algin is obtained from red algae, and carrageenan from brown algae. (c) Agar-agar is obtained from Gelidium and Gracilaria. (d) Laminaria and Sargassum are used as food.

Description : Which one of the following statements is wrong? (a) Algae increase the level of dissolved oxygen in the immediate environment. (b) Algin is obtained from red algae, and carrageenan from brown ... Agar-agar is obtained from Gelidium and Gracilaria. (d) Laminaria and Sargassum are used as food.

Last Answer : (b) Algin is obtained from red algae, and carrageenan from brown algae