GATE ES discipline:civil-and-environmental-engineering PYQs & Answers — Page 11

Questions 101–110 of 390. Imported answers require independent review unless marked reviewed.

A researcher added certain amount of HgCl₂ to water at pH 10. He calculated the expected concentration of mercury in the water. He asked his student to measure the concentration. His student used an instrument that can measure only the free metal, Hg²⁺. The student observed that the concentration measured by him was significantly less than the concentration calculated by the researcher. How can he explain the paradox to the researcher?

Explanation 1: Significant fraction of the mercury would have changed phase from aqueous to gaseous phase, thus leaving less mercury in the water

Explanation 2: Fraction of the mercury added to water would have formed aqueous complexes

Explanation 3: Fraction of the mercury added to water could have precipitated

Choose the correct option from the following

Your answerChoose one option.

only Explanation 1 is correct

Explanations 1 and 2 are correct

Explanations 1 and 3 are correct

Explanations 2 and 3 are correct

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Correctly label the speciation diagram below:

Diagram for Environmental Science and Engineering question 37

Your answerChoose one option.

I= PO₄³⁻, II= HPO₄²⁻, III= H₂PO₄⁻, IV= H₃PO₄

I= H₃PO₄, II= HPO₄²⁻, III= H₂PO₄⁻, IV=PO₄³⁻

I=H₃PO₄, II=H₂PO₄⁻, III=HPO₄²⁻, IV=PO₄³⁻

I= PO₄³⁻, II= H₂PO₄⁻, III= H₃PO₄, IV=HPO₄²⁻

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Consider the following statements on microbial metabolism (i) Utilization of carbon for cell synthesis is termed as anabolism. (ii) During catabolism, adenosine triphosphate (ATP) is converted into adenosine diphosphate (ADP). Choose the correct option from the following

Your answerChoose one option.

(i) and (ii) are correct

(i) and (ii) are incorrect

(i) is correct and (ii) is incorrect

(i) is incorrect and (ii) is correct

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Consider the following figure of an activated sludge process (ASP), depicting the flow (

), substrate (

), and microorganism concentration (

) at various points in the system, where subscripts “0”, “r”, “w”, “e”, and “i” indicate influent, recycle line, wastage, effluent, and flow from aeration tank to settling tank, respectively. Note that influent to the ASP has microbes too. V is volume of aeration tank.

Diagram for Environmental Science and Engineering question 39

Choose the correct option for net rate of formation of microorganisms in the system at steady state, from the following

Your answerChoose one option.

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Consider the following statements (i) Sound pressure changes with distance from the source (ii) Sound power is a property of the source (iii) Sound intensity is sound power per unit volume Choose the correct option from the following

Your answerChoose one option.

(i), (ii), and (iii) are correct

only (i) and (ii) are correct

only (i) and (iii) are correct

only (ii) and (iii) are correct

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At a pressure of 1 atmosphere and temperature of 25 °C, 365 μg m

of a pollutant corresponds to mixing ratio of 139 parts per billion (ppb). The atomic weights: C – 12, H – 1, O – 16, N – 14 and S – 32. Which one of the following options most closely represents the pollutant

Your answerChoose one option.

SO₂

NO₂

O₃

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Which option gives the best control strategies for Dioxins and Furans in the flue gas emitted from waste incineration facilities?

Your answerChoose one option.

Avoid burning polystyrene (PS) and polyethylene (PE); ensure the furnace temperature above 1000 °C; and use a bag filter for cleaning the flue gas.

Avoid burning polyvinyl chloride (PVC); quickly cool down the flue gas through the temperature range 400 - 250 °C; and use an activated carbon treatment for the flue gas.

Avoid burning food wastes; ensure the furnace temperature above 900 ± 50 °C; and use an electrostatic precipitator (ESP) for cleaning the flue gas.

Avoid burning metal bearing waste; ensure the flue gas temperature above 1000 °C; and use a venturi scrubber for cleaning the flue gas.

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Choose the correct option(s) from the following regarding the solubility in water

Your answerSelect all correct options. You can choose more than one.

Water is a polar molecule because of the asymmetric distribution of charge between the oxygen and hydrogen atoms of the water molecule.

In a water molecule, the electrons shared between oxygen and hydrogen are attracted more towards the hydrogen atom.

Non-polar compounds are highly soluble in water because of their strong interaction with water molecules.

Aromaticity and charge of molecules influence their solubility in water.

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If microbial growth occurs under substrate unlimited conditions, according to Monod’s kinetics, choose the correct option(s) from the following

Your answerSelect all correct options. You can choose more than one.

Microbial growth follows zero order with respect to substrate concentration.

Microbial growth follows first order with respect to substrate concentration.

Specific growth rate is half of maximum specific growth rate.

Specific growth rate is almost equal to maximum specific growth rate.

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Choose the correct option(s) for removing solids from water.

Your answerSelect all correct options. You can choose more than one.

chlorination

coagulation-flocculation-sedimentation followed by slow sand filtration

chlorination followed by aeration

slow sand filtration

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GATE ES discipline:civil-and-environmental-engineering PYQs

Question 36

Question 37

Question 38

Question 39

Question 40

Question 41

Question 42

Question 43

Question 44

Question 45