Q. Which of the following salts is the most common source of water hardness? Magnesium sulphateMagnesium bicarbonateMagnesium carbonateNone of the above Answer: Magnesium carbonate

Q. Which of the following claims about compressed natural gas is correct? It is a clean fuelIt is a harmful fuelIt is a polluting fuelAll of the above Answer: It is a clean fuel

Q. Which of the following is the effect of high BOD? More birth of aquatic plantsMore birth of fishesHigher dissolved oxygenLower dissolved oxygen Answer: Lower dissolved oxygen

Q. What do BOD and COD stand for? Biological Oxygen Demand and Chemical Oxygen Demand respectivelyChemical Oxygen Demand and Biological Oxygen Demand respectivelyBotanical Oxygen Demand and Chemical Oxygen Demand respectivelyBasic Oxygen Demand and Chemical Oxygen Demand respectively Answer: ...

Q. What is the excess growth of plankton in water due to the presence of nutrients called? Fungal bloomAlgal bloomPlantae bloomAnimal bloom Answer: Algal bloom

Q. Who utilizes the maximum amount of oxygen in the upstream of sewage discharge? AnimalsMicroorganismsHumansPlants Answer: Microorganisms

Q. What happens when the maximum amount of oxygen in the upstream of sewage discharge is utilized by microbes? Natality of aquatic plantsNatality of aquatic fishesMortality of aquatic creaturesMortality of bacteria Answer: Mortality of aquatic creatures

Q. How is the amount of biodegradable organic matter in sewage water estimated? Chemical Oxygen DemandPhysical Oxygen DemandBiological Oxygen DemandMathematical Oxygen Demand Answer: Biological Oxygen Demand

Q. Which sewage contains biodegradable waste such as organic matter? Medical wastePlastic wasteDomestic wasteWild waste Answer: Domestic waste

Q. Who is responsible for the degradation of biodegradable organic matter present in the domestic sewage? AnimalsHumansPlasticBacteria and other microbes Answer: Bacteria and other microbes

Q. Which materials are hard to remove from the polluted water? SandPlasticSolidsDissolved salts Answer: Dissolved salts

Q. Which materials are easily removed from the polluted water? LiquidSolidsDissolvedNutrients Answer: Solids