GATE ES topic:principles-water-chemistry PYQs & Answers — Page 2

Questions 11–20 of 22. Imported answers require independent review unless marked reviewed.

An industry discharges 2 million liters per day (MLD) of wastewater with a temperature of 45°C and a pH of 2, whereas the neighboring industry produces 3 MLD of wastewater with a temperature of 30°C and pH of 8. If both the wastewaters are mixed and carried through a pipeline, then the resultant pH of mixed wastewater is ______ (rounded off to 2 decimal places).

Neglect buffering capacity of the system and the temperature effect on pH.

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A person consumes 2.5 liters of water per day. The water quality test indicated that the supplied water has a Pb concentration of 0.6 mg/L. If the weight of the person is 75 kg, the exposure level for Pb for this person from this drinking water source is ______ mg/kg/day (rounded off to 2 decimal places).

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For testing alkalinity for a water sample, first phenolphthalein indicator is added. The water remains colorless. However, when a few drops of methyl orange is added to the sample, the color turns yellow. As per these observations, the correct choice is

Your answerChoose one option.

Absence of

and/or

but the presence of

ions in the sample

Presence of

and/or

but the absence of

ions in the sample

Absence of

and

ions in the sample

Presence of

and

ions in the sample

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The solubility of gas A is 16 mg/L in water and its vapor pressure is 0.042 atm at 25 °C. In a closed system, the gas phase concentration of A is

mol/L. Assuming Ideal gas constant (R) value as 0.0821 L-atm/mol-K, the concentration of gas A in water at 25 °C is __________ (in mg/L, rounded off to two decimal places).

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Specific conductance is used in water analysis to indirectly estimate dissolved solids. The measurements used in the method accounts for

Your answerChoose one option.

Cations only

All ions

Anions only

Un-ionized species

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Carbon dioxide is used in recarbonation process. A solution has 1 mole/L supersaturated calcium carbonate. Estimated amount of carbon dioxide (in grams) needed to completely convert calcium carbonate to calcium ions in 1 litre solution is

Your answerChoose one option.

44.000 gram

0.044 gram

40.000 gram

0.040 gram

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A solution has 0.01 mole/L zinc ions having pH of 6. Solubility product of zinc hydroxide is given as

(mole/L)³. Ignoring activity corrections, the ratio (rounded off to two decimal places) of reaction coefficient to solubility product would be __________.

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The Henry’s law constant of CO

M per atm in neutral water at 25°C. The dissolved CO

(i.e., CO

O) at equilibrium undergoes the following reactions.

O ⇌ H

+ HCO

(Equilibrium constant =

HCO

⇌ H

+ CO

(Equilibrium constant =

If ambient CO

concentration is 300 ppm, the total dissolved CO

(in μM, rounded off to one decimal place) is ________.

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What is the pH of a water sample having

concentration of 10 mg/L? The atomic weight of H is 1 g/mol.

Your answerChoose one option.

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A 200 mL sample of water has an initial pH = 9. In order to determine alkalinity, the sample was titrated using 0.02 N H₂SO₄ acid to an end point of pH = 4.5. In the titration, 25 mL of 0.02 N H₂SO₄ acid was required. What is the total alkalinity of the sample in ‘mg/L as NaHCO₃’?

[Atomic weight (g/mol): Ca = 40, Na = 23, H = 1, C = 12, S = 32, and O = 16]

Your answerChoose one option.

125

210

305

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GATE ES topic:principles-water-chemistry PYQs

Question 54

Question 63

Question 14

Question 50

Question 15

Question 21

Question 54

Question 55

Question 17

Question 31