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MCQOPTIONS
This section includes 854 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 801. |
The change in enthalpy, when a unit quantity of gas is absorbed by relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists) is termed as the |
| A. | differential heat of adsorption. |
| B. | heat of wetting. |
| C. | integral heat of adsorption. |
| D. | none of these. |
| Answer» B. heat of wetting. | |
| 802. |
When the temperature and humidity of air is low, we usually use __________ draft cooling tower. |
| A. | natural |
| B. | forced |
| C. | induced |
| D. | none of these |
| Answer» B. forced | |
| 803. |
Which of the following is the correct ternery diagram for liquid-liquid extraction system comprising of two pairs partly soluble (e.g., chlorobenzene-water-methyl ethyl ketone system) ? |
| A. | |
| B. | |
| C. | |
| D. | None of these. |
| Answer» B. | |
| 804. |
Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 x 10-3 kg mole/m2.s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is |
| A. | 5.6 x 10-4 |
| B. | 8.5 x 10-4 |
| C. | 5.6 x 10-3 |
| D. | 8.5 x 10-3 |
| Answer» C. 5.6 x 10-3 | |
| 805. |
Below is given an equilibrium moisture curve of a substance. State which regions represent free moisture and unbound moisture respectively. |
| A. | II, III |
| B. | II, IV |
| C. | IV, III |
| D. | IV, II |
| Answer» B. II, IV | |
| 806. |
Pick out the wrong statement pertaining to the analogy between equations of heat and mass transfer operations. |
| A. | Sherwood number in mass transfer is analogous to Nusselt number in heat transfer. |
| B. | Prandtl number in heat transfer is analogous to Schmidt number in mass transfer. |
| C. | Reynolds number in mass transfer is analogous to Grashoff number in heat transfer. |
| D. | Reynolds number remains the same in both heat and mass transfer. |
| Answer» D. Reynolds number remains the same in both heat and mass transfer. | |
| 807. |
Humidification involves mass transfer between a pure liquid phase and a fixed gas, which is |
| A. | insoluble in the liquid |
| B. | soluble in the liquid |
| C. | non-ideal in nature |
| D. | at a fixed temperature |
| Answer» B. soluble in the liquid | |
| 808. |
At a fixed total pressure, humidity depends only on the |
| A. | partial pressure of vapour in the mixture. |
| B. | heat capacity of the vapour. |
| C. | density of the vapour. |
| D. | none of these. |
| Answer» B. heat capacity of the vapour. | |
| 809. |
Leaching of uranium ore and gold ore is done in |
| A. | centrifugal extractor |
| B. | Pachuka tanks |
| C. | Bollman extractor |
| D. | none of these |
| Answer» C. Bollman extractor | |
| 810. |
Steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is called the __________ temperature. |
| A. | dry-bulb |
| B. | wet-bulb |
| C. | dew point |
| D. | adiabatic saturation |
| Answer» C. dew point | |
| 811. |
Hypersorption refers to a __________ process. |
| A. | fixed bed absorption |
| B. | moving bed absorption |
| C. | fixed bed adsorption |
| D. | moving bed adsorption |
| Answer» E. | |
| 812. |
Steam distillation is used to |
| A. | reduce the number of plates. |
| B. | avoid thermal decomposition of a component. |
| C. | increase the efficiency of separation. |
| D. | increase the total pressure of distillation. |
| Answer» C. increase the efficiency of separation. | |
| 813. |
The overall mass transfer co-efficient for the absorption of SO2 in air with dilute NaOH solution can be increased substantially by |
| A. | increasing the gas film co-efficient. |
| B. | increasing the liquid film co-efficient. |
| C. | increasing the total pressure. |
| D. | decreasing the total pressure. |
| Answer» B. increasing the liquid film co-efficient. | |
| 814. |
The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture. |
| A. | composition |
| B. | temperature |
| C. | total pressure |
| D. | all (a), (b) and (c) |
| Answer» C. total pressure | |
| 815. |
Agitator is provided in a crystalliser for |
| A. | avoiding deposition on cooler surfaces. |
| B. | formation of nuclei. |
| C. | crystal growth. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 816. |
Chemisorption (chemical adsorption) is |
| A. | same as "Van der Waals" adsorption. |
| B. | characterised by adsorption of heat. |
| C. | an irreversible phenomenon. |
| D. | a reversible phenomenon. |
| Answer» D. a reversible phenomenon. | |
| 817. |
In the absorption of ammonia in water, the main resistance to absorption is by the __________ phase. |
| A. | liquid |
| B. | gas |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» C. both (a) & (b) | |
| 818. |
Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant. |
| A. | agitated vessel |
| B. | sieve tray column |
| C. | bubble cap column |
| D. | packed tower |
| Answer» B. sieve tray column | |
| 819. |
Out of two equilibrium curves, first one lies above the diagonal and the second lies below the diagonal in the x-y plot. It means that separation by distillation is |
| A. | not possible in the second case unless vacuum is applied. |
| B. | not possible in the second case unless high pressure is applied. |
| C. | more readily done in the second case compared to first one. |
| D. | none of these |
| Answer» D. none of these | |
| 820. |
In case of absorption & stripping, the interface of the liquid & gas phases are present in equilibrium, when the diffusional resistance of __________ is zero. |
| A. | interface |
| B. | gas phase |
| C. | liquid phase |
| D. | all 'a', 'b' & 'c' |
| Answer» B. gas phase | |
| 821. |
Rayleigh equation applies to __________ distillation. |
| A. | differential |
| B. | flash |
| C. | equilibrium |
| D. | molecular |
| Answer» B. flash | |
| 822. |
The operating cost of a distillation column at minimum reflux ratio is |
| A. | minimum |
| B. | maximum |
| C. | infinite |
| D. | zero |
| Answer» B. maximum | |
| 823. |
Dryer widely used in a textile industry is __________ dryer. |
| A. | festoon |
| B. | cylinder |
| C. | conveyor |
| D. | tunnel |
| Answer» D. tunnel | |
| 824. |
The binary diffusivity in gases does not depend upon the |
| A. | pressure |
| B. | temperature |
| C. | nature of the components |
| D. | none of these |
| Answer» E. | |
| 825. |
Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number. |
| A. | Sherwood |
| B. | Schmidt |
| C. | Peclet |
| D. | Stanton |
| Answer» B. Schmidt | |
| 826. |
Drying of a solid involves __________ transfer. |
| A. | only heat |
| B. | only mass |
| C. | both heat and mass |
| D. | none of these |
| Answer» D. none of these | |
| 827. |
Mass transfer co-efficient 'K' according to penetration theory varies with mass dif-fusivity as |
| A. | D0.5 |
| B. | D |
| C. | 1/D |
| D. | D1.5 |
| Answer» B. D | |
| 828. |
Psychrometry deals with the properties of gas-vapor mixture. Humidity can be determined by the measurement of the __________ of a fibre. |
| A. | electrical resistance |
| B. | thermal conductivity |
| C. | strength |
| D. | none of these. |
| Answer» B. thermal conductivity | |
| 829. |
The term "cooling range" in a cooling tower refers to the difference in the temperature of |
| A. | cold water leaving the tower and the wet bulb temperature of the surrounding air. |
| B. | hot water entering the tower and the wet bulb temperature of the surrounding air. |
| C. | hot water entering the tower and the cooled water leaving the tower. |
| D. | none of these |
| Answer» D. none of these | |
| 830. |
In a solution containing 0.30 Kg mole of solute and 600 kg of solvent, the molality is |
| A. | 0.5 |
| B. | 0.6 |
| C. | 2 |
| D. | 1 |
| Answer» B. 0.6 | |
| 831. |
In a binary system, separation is very efficient, when the relative volatility is |
| A. | 1 |
| B. | > 1 |
| C. | < 1 |
| D. | 0.5 |
| Answer» C. < 1 | |
| 832. |
Drying operation under vacuum is carried out to |
| A. | dry those materials which have very high unbound mositure content. |
| B. | reduce drying temperature. |
| C. | increase drying temperature. |
| D. | dry materials having high bound moisture content. |
| Answer» C. increase drying temperature. | |
| 833. |
Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when |
| A. | extracting solvent is cheaply & abundantly available. |
| B. | one of the liquid components is heat sensitive. |
| C. | viscosity of liquid components is very high. |
| D. | one of the liquid components has very high affinity towards the solvent. |
| Answer» E. | |
| 834. |
Make up water is required in a cooling tower to replace the water lost by |
| A. | evaporation |
| B. | drift |
| C. | blowdown and leakage |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 835. |
In a gas-liquid absorption coloumn, for obtaining the maximum absorption efficiency |
| 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. |
| Answer» D. by passing should be completely avoided. | |
| 836. |
In distillation columns, the number of bubble caps per tray primarily depends upon the |
| A. | allowable liquid velocity. |
| B. | allowable gas velocity. |
| C. | allowable gas and liquid velocities. |
| D. | feed composition. |
| Answer» D. feed composition. | |
| 837. |
Perforated plate towers are unique for solvent extraction because, they provide |
| A. | higher contact area. |
| B. | better contact of the phase. |
| C. | repeated coalescence & redispersion of the drop phase. |
| D. | none of these. |
| Answer» D. none of these. | |
| 838. |
Fenske equation determines the |
| A. | maximum number of ideal plates. |
| B. | height of the distillation column. |
| C. | minimum number of theoretical plates. |
| D. | optimum reflux ratio. |
| Answer» D. optimum reflux ratio. | |
| 839. |
The McCabe Δ L law states that the |
| A. | molar heats of vaporisation of components are nearly equal. |
| B. | linear crystal growth rate depends on the degree of supersaturation. |
| C. | linear crystal growth rate does not depend on the crystal size. |
| D. | linear crystal growth rate depends on the crystal size. |
| Answer» D. linear crystal growth rate depends on the crystal size. | |
| 840. |
As the reflux ratio in a distillation coloumn is increased from the minimum, the |
| A. | slope of the operating line in stripping section decreases. |
| B. | number of plates decreases very slowly first and then more and more rapidly. |
| C. | total cost first decreases and then increases. |
| D. | liquid flow increases while the vapor flow decreases for a system. |
| Answer» D. liquid flow increases while the vapor flow decreases for a system. | |
| 841. |
Which of the following parameters remains constant during chemical dehumidifica-tion? |
| A. | Dry bulb temperature |
| B. | Partial pressure of vapour |
| C. | Wet bulb temperature |
| D. | None of these |
| Answer» B. Partial pressure of vapour | |
| 842. |
Steam distillation is used for separation of high boiling |
| A. | substances from non-volatile impurities. |
| B. | volatile impurity from still higher boiling substances. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 843. |
Boiling point diagram is |
| A. | not affected by pressure. |
| B. | affected by pressure. |
| C. | a plot of temperature vs. liquid composition. |
| D. | a plot of temperature vs. vapour composition. |
| Answer» C. a plot of temperature vs. liquid composition. | |
| 844. |
Total reflux in a distillation operation requires minimum |
| A. | reboiler load |
| B. | number of plates |
| C. | condenser load |
| D. | all (a), (b) and (c) |
| Answer» C. condenser load | |
| 845. |
The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = __________ |
| A. | 1 |
| B. | 0.5 |
| C. | 10 |
| D. | 0 |
| Answer» B. 0.5 | |
| 846. |
Which of the following is a suitable absorbent for removal of H2S from natural gas ? |
| A. | Vetrocoke solution |
| B. | Monoethanol amine (MEA) |
| C. | Dilute |
| D. | Hot water |
| Answer» C. Dilute | |
| 847. |
When both the fluids flow concurrently in an absorber, the slope of the operating line is |
| A. | #NAME? |
| B. | #NAME? |
| C. | 1 |
| D. | -1 |
| Answer» B. #NAME? | |
| 848. |
Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be |
| A. | cooled |
| B. | humidified |
| C. | both (a) & (b) |
| D. | dehumidified |
| Answer» C. both (a) & (b) | |
| 849. |
__________ is used as an 'entrainer' for the separation of acetic acid-water mixture by distillation. |
| A. | Furfural |
| B. | Benzol |
| C. | Butyl acetate |
| D. | Hexane |
| Answer» D. Hexane | |
| 850. |
Relative humidity is the ratio of the |
| A. | partial pressure of the vapour to the vapour pressure of the liquid at room temperature. |
| B. | partial pressure of the vapour to the vapour pressure of the liquid at gas temperature. |
| C. | actual humidity to saturation humidity. |
| D. | none of these |
| Answer» C. actual humidity to saturation humidity. | |