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
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
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
Description : The phenomenon occuring during pumping of a liquid solution containing dissolved gases, which may come out of the solution giving rise to gas pockets, is termed as (A) Evaporation (B) Cavitation (C) Sublimation (D) Stripping
Last Answer : (B) Cavitation
Description : Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of __________ present in it. (A) Coal ash (B) Potassium cyanide (C) Ortho-xylene (D) None of these
Last Answer : (B) Potassium cyanide
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.
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
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).
Description : Dissolved oxygen (DO) should not be less than _____________ mg/L of water. (a) 14 (b) 3 (c) 5 (d) 2
Last Answer : Ans:(c)
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
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
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
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
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
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
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
Description : How dissolved oxygen control is achieved in feed water system?
Last Answer : Hydrazine is added to feed water system to control dissolved oxygen.
Description : Dissolved oxygen content in river water is around __________ ppm. (A) 5 (B) 100 (C) 250 (D) 500
Last Answer : (A) 5
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
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
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
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
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)
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
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)
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
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
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
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
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
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
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
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
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
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.
Description : What take oxygen during the lung respiration and oxygen gas is dissolved in the blood stream?
Last Answer : What is the answer ?
Description : Where is dissolved oxygen likely to be lowest?
Last Answer : Need answer
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.
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.
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
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
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
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)
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
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.
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
Description : Presence of carbonaceous matter in the sewage (A) Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures (B) Reduces sulphate ions to sulphides causing obnoxious ... quantity of chlorine used for its purification (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Sunlight (A) Helps growth of bacterias (B) Impedes growth of algae (C) Increases dissolved oxygen content (D) Reduces turb
Last Answer : (B) Impedes growth of algae
Description : Which one of the following tests employs Ethylene Diamine Tetra Acetic Acid as a titrating agent? (a) Chlorides (b) Dissolved oxygen (c) Hardness (d) Residual chlorine
Last Answer : (c) Hardness
Description : Eutrophication results in reduction of a) Dissolved nitrate b) Dissolved Oxygen c) Mineral salts d) Parasitic protozoa.
Last Answer : b) Dissolved Oxygen