Description : Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried ... contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane
Last Answer : ANS: C
Description : If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen
Last Answer : ANS: A
Description : If the flame of a miner’s safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen
Last Answer : ANS: B
Description : If the flame of a miner’s safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains A. Hydrogen sulphide B. Carbon dioxide C. Methane D. Oxygen
Description : Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1
Description : The detention time (t) of a settling tank, may be defined as the time required for A. A particle to travel along its length B. A particle to travel from top surface to bottom sludge zone C. The flow of sewage to fill the tank D. None of these
Description : The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %
Description : For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these
Description : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above
Last Answer : ANS: D
Description : In sewers the gas generally found, is A. Hydrogen sulphide (H2S) B. Carbon dioxide (CO2) C. Methane (CH4) D. All the above
Description : Which one of the following gases is most significant as air pollutant? A. Carbondioxide B. Oxygen C. Nitrogen D. Sulphur-dioxide
Description : The digested sludge from septic tanks, is removed after a maximum period of A. 3 years B. 3.5 years C. 4 years D. 5 years
Description : The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these
Description : The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres
Description : Sludge banks are formed if sewage is disposed of in A. Rivers B. Seas C. Lakes D. None of these
Description : pH value of sludge during alkaline regression stage, is A. More than 7 B. Less than 7 C. Less than 6 D. More than 6
Description : In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action
Description : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days
Description : The rate of accumulation of sludge in septic tanks is recommended as A. 30 litres/person/year B. 25 litres/person/year C. 30 litres/person/month D. 25 litres/person/month
Description : Skimming tanks are A. Used to remove the grease and oil B. Those from which sludge is skimmed out C. Tanks provided with self- cleansing screens D. Improved version of grit chambers
Description : Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above
Description : The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets
Description : The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these
Description : 11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days
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 : A well oxidized sewage contains nitrogen mainly as A. Nitrates B. Nitrites C. Free ammonia D. None of these
Description : During photosynthesis in plants, the gas evolved is - (1) Carbon dioxide (2) Nitrogen (3) Oxygen (4) Hydrogen
Last Answer : (3) Oxygen Explanation: Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism ... , through primary production, or indirectly, as the ultimate source of the energy in their food.
Description : During photosynthesis the liberated gas is (1) Carbon dioxide (2) oxygen (3) Nitrogen (4) Hydrogen
Last Answer : (2) oxygen Explanation: Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism ... water, releasing oxygen as a waste product.' Photosynthesis is vital for all aerobic life on Earth.
Description : The name of unreactive gas is – (1) Carbon dioxide (2) Hydrogen (3) Nitrogen (4) Oxygen
Last Answer : (3) Nitrogen Explanation: Nitrogen is chemically unreactive because it has a strong triple bond which binds the two nitrogen atoms together making it harder for it to be broken. It does not burn, and at ordinary temperatures it does not react with other elements.
Description : The gas that is used in the manufacture of vanaspati ghee is - (1) Oxygen (2) Carbon dioxide (3) Hydrogen (4) Nitrogen
Last Answer : (3) Hydrogen Explanation: Hydrogenation - to treat with hydrogen - is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. ... is for the processing of vegetableoils (fats to give margarine and related spreads and shortenings).
Description : Which gas is used to manufacture vanaspati from vegetable oil is - (1) carbon dioxide (2) nitrogen (3) oxygen (4) hydrogen
Last Answer : (4) hydrogen Explanation: Hydrogen is used to manufacture vanaspati from vegetable oil.
Description : Which Gas is included in Fry Chips Packets for safety? A. Nitrogen gas (Answer) B. Carbon dioxide C. Oxygen D. Hydrogen
Last Answer : A. Nitrogen gas (Answer)
Description : Facultative anaerobes can live with or without _____ gas. a. carbon dioxide b. hydrogen c. nitrogen d. oxygen
Last Answer : d. oxygen
Description : Baker’s yeast produce gas which helps in rising of dough is ____________. a) oxygen b)hydrogen c)carbon dioxide d)nitrogen
Last Answer : c)carbon dioxide
Description : When vinegar and baking soda are mixed together, w gas is formed? w) oxygen x) nitrogen y) carbon dioxide z) hydrogen
Last Answer : ANSWER: Y -- CARBON DIOXIDE
Description : During photosynthesis in plants, the gas evolved is (1) Carbon dioxide (2) Nitrogen (3) Oxygen (4) Hydrogen
Last Answer : Oxygen
Description : During photosynthesis the liberated gas is : (1) Carbon dioxide (2) Oxygen (3) Nitrogen (4) Hydrogen
Description : The name of unreactive gas is (1) Carbon dioxide (2) Hydrogen (3) Nitrogen (4) Oxygen
Last Answer : Nitrogen
Description : The gas that is used in the manufacture of vanaspati ghee is : (1) Oxygen (2) Carbon dioxide (3) Hydrogen (4) Nitrogen
Last Answer : Hydrogen
Description : In an acid base reaction which product is produced along with a salt? (1) Hydrogen gas (2) Oxygen gas (3) Carbon dioxide (4) Water
Last Answer : (4) Water Explanation: When an acid and a base are placed together, they read to neutralize the acid and base properties, producing a salt. The H(+) cation of the acid combines with the OH(-) anion of the base to form water.
Description : Oxidation process results in the formation of A. Carbon dioxide B. Nitrates C. Sulphates D. All the above
Description : Of all the gases present in the air, which one of the following is the highest in percentage? (a) Carbon dioxide (b) Hydrogen (c) Nitrogen (d) Oxygen
Last Answer : Ans:(c)
Description : The atmosphere of the primitive earth before origin of life consisted of: (a) Nitrogen, Oxygen, Ammonia, and Water vapour (b) Methane, Ammonia, Hydrogen, and Water vapour (c) Nitrogen, Oxygen, Water, and Carbon dioxide (d) Ammonia, Water, Oxygen, and Hydrogen
Last Answer : Ans:(b)
Description : To carry out photosynthesis plants require – (1) Oxygen (2) Carbon-dioxide (3) Nitrogen (4) Hydrogen
Last Answer : (2) Carbon-dioxide Explanation: In photosynthesis, carbon dioxide is converted into sugars in a process called carbon fixation. Carbon fixation is a redox reaction, so photosynthesis needs to ... the electrons needed to convert carbon dioxide into a carbohydrate, which is a reduction reaction.
Description : The highest volume of gases in lower atmosphere is comprised of - (1) Hydrogen (2) Carbon dioxide (3) Oxygen (4) Nitrogen
Last Answer : (4) Nitrogen Explanation: There are a number of atmospheric gases which make up air. In the lower atmosphere or troposphere, the main gases are nitrogen and oxygen, which make up 78% and 21% of the volume of air respectively. The remaining 1% of the atmospheric gases is made up of trace gases.
Description : The bubbles in Chanmpagne and Soda are - (1) Nitrogen (2) Oxygen (3) Carbon dioxide (4) Hydrogen
Last Answer : (4) Hydrogen
Description : Silver gets corroded due to ______ in air. (1) Oxygen (2) Hydrogen Sulphide (3) Carbon dioxide (4) Nitrogen
Last Answer : (2) Hydrogen Sulphide Explanation: Silver is a fairly stable metal and under normal circumstances does not corrode quickly. However, it is particularly susceptible to the effects of the sulfide ... atmosphere, especially in marine environment, and readily forms a surface tarnish of silver sulphide.
Description : The major constituent of air is – (1) nitrogen (2) carbon dioxide (3) oxygen (4) hydrogen
Last Answer : (1) nitrogen Explanation: Depending on various geographical locationsthese may change, but for the most part air is made up of 78% nitrogen (N2), 21% oxygen (O2), and trace amounts of ... and mostly inert diatomic gas at standard conditions, constituting 78.09% by volume of Earth's atmosphere.
Description : Which of the following gases do plants and trees give out during photosynthesis? A. Hydrogen B. Nitrogen C. Oxygen (Answer) D. Carbon dioxide
Last Answer : C. Oxygen (Answer)
Description : What is Dry Ice? A. Solid Oxygen B. Solid Carbon Dioxide (Answer) C. Solid Hydrogen D. Solid Nitrogen
Last Answer : B. Solid Carbon Dioxide (Answer)