chemical engineering Mcqs
1851. In a gas-liquid absorption column, for obtaining the maximum absorption efficiency____________________?
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A. Liquid stream should be distributed uniformly

B. Gas stream should be distributed uniformly

C. Both gas as well as liquid streams should be distributed uniformly

D. By passing should be completely avoided

E. wer: Option C

1852. Pick out the correct statement ?
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A. ms</strong>

B. Vegetable oils are classified as drying, non-drying and semi drying oils depending upon their

C. ty acids content

D. All vegetable oils except coconut oil, contains fatty acids having more than sixteen carbon

E. There is no difference between a fat and an oil so far as its physical properties are concerned

F. A fat is converted into oil by its hydrogenation

1853. Degree of freedom for leaching and solvent extraction process is_____________________?
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A. 1

B. 0

C. 3

D. 2

1854. If f is defined as above, then which of the following applies to a feed at dew point ?
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A. 0 < f < 1

B. f = 1

C. f 1

1855. With the lowering of equilibrium pressure, at a given temperature, the amount of adsorbate on the adsorbent ?
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A. Decreases

B. Either A. or B., depends on the system

C. Remain same

D. Increases

1856. Which of the following has the same dimension as mass diffusivity ?
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A. Momentum flux

B. Kinematic viscosity

C. Thermal diffusivity

D. Both B. and C.
1857. Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty ?
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A. Wetted wall tower

B. Bubble cap tower

C. Grid tray tower

D. Perforated tray tower

1858. Sodium bicarbonate is produced during soda ash manufacture using a _______________ tower?
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A. None of these

B. Plate

C. Baffle

D. Packed

1859. The equilibrium liquid composition compared to the vapor composition in case of________________?
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A. Either more or less; depends on the system

B. Less

C. More

D. Same

E. otropic mixture is

1860. The percentage humidity is less than the relative humidity only at __________________ percent humidity?
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A. Zero

B. Hundred

C. Both zero and hundred

D. None of these

1861. In case of constant underflow extraction operation, the _______________________ at all solute concentration?
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A. Solids are drained to the same extent

B. Ratio of the insoluble to solution is constant

C. Both A. & B.

D. Neither A. nor B.

1862. Binary distillation involves the mass transfer by ______________________ at the gas-liquid interface?
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A. Unidirectional diffusion from gas to liquid phase

B. A counter diffusion at an almost equal molar rate

C. Unidirectional diffusion from liquid to gas phase

D. Either A. or B.

1863. The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is____________________?
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A. 2

B. 0.5

C. 150

D. 50

1864. ___________________ extractor uses centrifugal force for separating the two phases?
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A. Treybal

B. Podbielniak

C. None of these

D. Scheibel

1865. The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives___________________?
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A. High pressure drop and low hold up

B. High pressure drop and high hold up

C. Low pressure drop and low hold up

D. Low pressure drop and high hold up

1866. The ratio of Murphree plate efficiency to point efficiency is always > 1 in a _______________ flow model?
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A. Plug

B. Perfectly mixed

C. Both A. & B.

D. Neither A. nor B.

1867. Pick out the wrong statement?
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A. Eosin requirement in tallow soap is about 40-50% which fastens the lather formation, softens

B. tea, blood etc</strong>

C. hard soaps and increases its cleansing action

D. Soap powder is prepared by mixing soap with hydrated sodium carbonate

E. Detergents differ from soaps in their action in hard water

F. Tarnish inhibitor (e.g., Benzotriazole) is added in soap to facilitate the removal of stains due
1868. __________________ is concerned with the adsorption equilibria?
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A. Ficks law

B. Freundlich equation

C. None of these

D. Gibbs equation

1869. In case of an ideal solution, the total vapor pressure varies ______________ with the composition expressed as mole fraction?
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A. Exponentially

B. None of these

C. Linearly

D. Inversely

1870. Even though bubble cap towers are very effective for humidification operation, they are not used commonly in industries, because of the_________________?
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A. None of these

B. High pressure drop of the gas

C. High evaporation losses of water

D. Difficulty in its fabrication

1871. For a single component absorber, the operating line is straight only when plotted in term of ______________ units?
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A. Mole fraction

B. Mole ratio

C. None of these

D. Partial pressure

1872. Molecular distillation is_____________________?
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A. High temperature distillation

B. For heat-sensitive materials

C. Very low pressure distillation

D. Both B. and C.
1873. NSc/NPr is called the______________________?
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A. Lewis number

B. Psychrometric ratio

C. Sherwood number

D. Stanton number

1874. The most economical range of absorption factor is____________________?
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A. 1.25 to 2

B. 0 to 0.5

C. 0 to 3

D. 5 to 15

1875. The relation, Sc = Pr = 1, is valid, when the mechanism of ______________ transfer is same?
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A. Heat, momentum and mass

B. Mass and momentum

C. Heat and mass

D. Heat and momentum

1876. _______________ extractor is used for the concentration of radioactive nuclear waste?
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A. Pulsed column

B. Sieve plate

C. Mixer-settler

D. Bollman

1877. Gaseous diffusivity at atmospheric pressure is of the order of _____________________ cm2/second?
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A. 1 to 5

B. > 10

C. 1

D. 5 to 10

1878. Schmidt number and Lewis number for pure air at atmospheric conditions are respectively__________________?
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A. < 1 and ? 1

B. 0 and ? 1

C. 1 and 0

D. > 1 and ? 1

1879. With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency____________________?
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A. Increases

B. Remain same

C. May increase or decrease; depends on individual design

D. Decreases

1880. Which of the following is a suitable absorbent for removal of H2S from natural gas ?
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A. Monoethanolamine (MEA)

B. Hot water

C. Dilute

D. Vetrocoke solution

1881. In extraction, as the temperature increases, the area of heterogeneity (area covered by binodal curve)________________?
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A. None of these

B. Increases

C. Remains unchanged

D. Decreases
1882. Unit of molal diffusivity is____________________?
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A. cm2/sec gm . mole

B. gm moles/cm. sec

C. gm moles/cm2 . sec

D. gm moles/cm2. sec

1883. According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to_________________?
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A. f

B. f/2

C. 2f

D. 1/f

1884. The Hatta number is important in______________________?
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A. Gas absorption without chemical reaction

B. Gas absorption with chemical reaction

C. Multi-component distillation

D. Binary distillation

1885. Wet bulb and dry bulb temperatures becomes identical at _______________ percent saturation curve?
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A. None of these

B. 50

C. 100

D. 78

1886. Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maxi-mum equilibrium moisture ?
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A. Anthracite coal

B. Bamboo

C. Rag paper

D. Inorganic solids

1887. In case of unsaturated air____________________?
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A. Dew point < wet bulb temperature

B. Wet bulb temperature < dry bulb temperature

C. Both A. and B.

D. Neither A. not B.

1888. Moisture contained by a substance in excess of the equilibrium moisture is called the _______________ moisture?
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A. Free

B. Unbound

C. Bound

D. Critical

1889. The solvent used in liquid extraction should not have high latent heat of vaporisation, because ______________________?
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A. It cannot be recovered by distillation

B. The pressure drop and hence the pumping cost will be very high

C. Its recovery cost by distillation may be prohibitively high

D. It will decompose while recovering by distillation

1890. The suitable evaporator for concentration of foaming liquids is a ______________________ evaporator?
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A. Short tube

B. Long tube

C. Falling film

D. Vacuum

1891. Ordinary diffusion process is also called ______________ diffusion?
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A. Pressure

B. Thermal

C. Concentration

D. Forced

1892. In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer?
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A. Less than 1 kg of C is transferred to B

B. No amount of C is transferred to B

C. The entire amount of C is transferred to solvent B

D. Less than 2 kg but more than 1 kg of C is transferred to solvent B

1893. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid _______________ that in dry packed tower ?
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A. Is same as

B. Is greater than

C. Cannot be predicted as data are insufficient

D. Is lower than

1894. The value of NA/(NA + NB) for steady state molecular diffusion of gas A through nondiffusing gas B is____________________?
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A. 2

B. ?

C. 1

D. 0.5

1895. During constant rate drying period, vaporisation rate per unit drying surface area _____________________?
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A. Decreases with time

B. Does not affect the moisture content of the wet solid

C. Does not change with time

D. Increases with time

1896. Pick out the wrong statement ?
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A. Insecticides acting on the insects through the respiratory system are called fumigants

B. Chloral is obtained by the chlorination of ethyl alcohol

C. Benzene hexachloride is not a contact insecticide

D. DDT is manufactured by the condensation of chlorobenzene with chloral at 30C in presence

E. oleum, which is a highly exothermic reaction

1897. Ammonia present in the coke oven gas is removed by washing with___________________?
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A. Dilute HCl

B. Ethanolamine

C. Caustic solution

D. Dilute ammoniacal liquor
1898. H2S present in naphtha reformed gas is removed by absorbing with___________________?
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A. Ethanolamine

B. Vacuum gas oil

C. K2CO3

D. HCl

1899. The ratio of Murphree plate efficiency to point efficiency is 1 in a ______________________ flow model?
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A. Plug

B. Perfectly mixed

C. Both A. & B.

D. Neither A. nor B.

1900. In case of absorption, both the operating and equilibrium lines will be straight for______________?
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A. Isothermal operation

B. Dilute solutions

C. None of these

D. Dilute solutions and isothermal operation