chemical engineering MCQs – Page 96

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
1901. Separation of two volatile liquids by distillation makes use of their________________________?
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A. Density difference

B. Relative volatility

C. Solubility

D. Selectivity

1902. Use of packed towers for distillation is generally limited to the____________________?
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A. Vacuum distillation

B. Small sizes

C. Multi-component distillation

D. High pressure operation

1903. The wet and dry bulb temperature for a vapour-gas mixture are 25C and 30C respectively. If the mixture is heated to 45C at constant pressure, the wet bulb temperature will be ______________ C?
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A. 25

B. < 25

C. > 25

D. 25

1904. Packed column distillation is limited to the column _____________ metres?
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A. Height < 6

B. Diameter < 0.6

C. Both A. & B.

D. Neither A. nor B.

1905. With increase in temperature, the mutual solubility of two liquids___________________?
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A. Remains unchanged

B. Decreases exponentially

C. Increases

D. Decreases

1906. In most of the vacuum crystalliser, vacuum is generally produced by means of a_____________________?
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A. Compressed air jet

B. Steam jet ejector with a barometric condenser

C. Suction pump

D. None of these

1907. HETP is numerically equal to HTU, only when the operating line ______________________?
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A. Lies above the equilibrium line

B. Is far from the equilibrium line

C. Lies below the equilibrium line

D. And equilibrium lines are parallel
1908. For a ternary mixture, in which equilateral triangular co-ordinate is used in leaching and extraction, a _______________ of the equilateral triangular co-ordinates?
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A. Pure component is represented by the apex

B. Ternary mixture is represented by the sides

C. Binary mixture is represented by the apex

D. Binary mixture is represented by any point inside

1909. At constant pressure, with increase of temperature, the dew point will ________________________?
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A. Increase

B. Remain unchanged

C. Increase/decrease; depends on the temperature

D. Decrease

1910. If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be _______________ percent?
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A. 100

B. < 100

C. > 100

D. None of these

1911. Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in ______________ tower?
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A. Bubble cap

B. Wetted wall

C. Perforated tray

D. Packed

1912. In physical terms, Schmidt number means _________________?
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A. Thermal diffusivity/mass diffusivity

B. Thermal diffusivity/momentum diffusivity

C. Momentum diffusivity/mass diffusivity

D. Mass diffusivity/thermal diffusivity

1913. Bollman extractor___________________?
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A. Is a static bed leaching equipment

B. Is used for extraction of oil from oilseed

C. Is a centrifugal extractor

D. Employs only counter-current extraction

1914. Absorption (liquid-gas system) with evolution of heat as compared to isothermal absorption results in_________________?
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A. Decreased solute solubility

B. Large number of trays

C. All A., B. and C.

D. Large minimum liquid to gas (L/G) ratio

1915. The critical moisture content in case of drying indicates the _______________ rate period?
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A. None of these

B. Beginning of falling

C. Beginning of constant

D. End of falling

1916. Blowdown in a cooling tower____________________?
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A. All A., B. & C.

B. Increases the scale forming tendencies of water

C. Is undesirable

D. salt and impurities</strong>

E. Means discarding a small fraction of circulating water to prevent and limit the concentration
1917. Drift in a cooling tower is ___________________?
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A. All A., B. & C.

B. The water entrained by the circulating air

C. Dependent on the water lost by evaporation

D. Desirable

1918. The apex of an equilateral-triangular coordinate (in ternary liquid system) represents a/an ___________________?
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A. Ternary mixture

B. Binary mixture

C. Insoluble binary system

D. Pure component
1919. Tea percolation employs___________________________?
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A. Absorption

B. None of these

C. Leaching

D. Liquid-liquid extraction

1920. The diffusivity D. in a binary gas mixture is related to the pressure (P) as___________________?
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A. D ? 1/P1.5

B. D ? 1/P

C. D ? P0.5

D. D ? 1/P0.5