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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.
| 751. |
Rose oil is extracted from rose leaves using __________ distillation. |
| A. | high pressure |
| B. | low pressure |
| C. | extractive |
| D. | steam |
| Answer» E. | |
| 752. |
As per Gilliland's equation, the diffusivity is |
| A. | directly proportional to 'T1.5'. |
| B. | inversely proportional to 'P'. |
| C. | dependent on the molecular volume & molecular weight of components. |
| D. | all 'a', 'b' & 'c'. |
| Answer» E. | |
| 753. |
1 kg of a saturated aqueous solution of a highly soluble component A at 60°C is cooled to 25°C. The solubility limits of A are (0.6 kgA/kg water) at 60°C and (0.2 kgA/kg water) at 25°C. The amount in kg of the crystals formed is |
| A. | 0.4 |
| B. | 0.25 |
| C. | 0.2 |
| D. | 0.175 |
| Answer» D. 0.175 | |
| 754. |
Pressure drop through plate tower as compared to that through packed tower, for the same duty will be |
| A. | less |
| B. | more |
| C. | equal |
| D. | either (a) or (b); depends on the packing height |
| Answer» C. equal | |
| 755. |
NSc/NPr is called the |
| A. | psychrometric ratio |
| B. | Lewis number |
| C. | Sherwood number |
| D. | Stantan number |
| Answer» C. Sherwood number | |
| 756. |
The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is |
| A. | natural draft cooling tower |
| B. | induced draft cooling tower |
| C. | spray chamber |
| D. | none of these |
| Answer» D. none of these | |
| 757. |
On addition of solute in the solvent, the __________ of the solution decreases. |
| A. | boiling point |
| B. | freezing point |
| C. | vapour pressure |
| D. | both (b) and (c) |
| Answer» E. | |
| 758. |
Relative volatility does not change appreciably with the change in |
| A. | temperature |
| B. | vapour pressure of either component |
| C. | total pressure |
| D. | none of these |
| Answer» B. vapour pressure of either component | |
| 759. |
Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a |
| A. | higher dew point. |
| B. | higher absolute (specific) humidity. |
| C. | higher relative humidity |
| D. | higher wet bulb temperature. |
| Answer» D. higher wet bulb temperature. | |
| 760. |
Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ coloumn. |
| A. | spray |
| B. | packed |
| C. | bubble cap plate |
| D. | wetted wall |
| Answer» E. | |
| 761. |
Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate. |
| A. | increases |
| B. | decreases |
| C. | does not affect |
| D. | exponentially increases |
| Answer» C. does not affect | |
| 762. |
Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for |
| A. | constant molal overflow |
| B. | total reflux |
| C. | constant relative volatility |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 763. |
Which of the following unit operations makes use of Thiele-Geddes equation ? |
| A. | Liquid-liquid extraction |
| B. | Solid-liquid extraction |
| C. | Multicomponent absorption with chemical reaction |
| D. | Multicomponent distillation. |
| Answer» E. | |
| 764. |
Which of the following is not a batch drier? |
| A. | Truck drier |
| B. | Agitated pan drier |
| C. | Fluidised bed drier |
| D. | Vacuum shelf drier |
| Answer» D. Vacuum shelf drier | |
| 765. |
Molecular seives are regenerated by heating to __________ °C. |
| A. | < 150 |
| B. | 200-330 |
| C. | > 500 |
| D. | > 1000 |
| Answer» C. > 500 | |
| 766. |
Which of the following parameters remains almost constant during adiabatic saturation of unsaturated air ? |
| A. | Dry bulb temperature |
| B. | Dew point |
| C. | Wet bulb temperature |
| D. | None of these |
| Answer» D. None of these | |
| 767. |
Absorption accompanied with chemical reaction is exemplified by the absorption of |
| A. | ammonia in water. |
| B. | benzol present in coke oven gas by wash oil. |
| C. | SO2 in alkaline solution. |
| D. | all (a), (b) and (c). |
| Answer» D. all (a), (b) and (c). | |
| 768. |
__________ extractor uses centrifugal force for separating the two phases. |
| A. | Treybal |
| B. | Schiebel |
| C. | Podbielniak |
| D. | None of these |
| Answer» D. None of these | |
| 769. |
Deairation (removal of O2) of water is done by |
| A. | rectification |
| B. | absorption |
| C. | ion-exchange |
| D. | adsorption |
| Answer» D. adsorption | |
| 770. |
Back-trapping in a distillation column |
| A. | increases tray efficiency. |
| B. | decreases tray efficiency. |
| C. | reduces pressure drop. |
| D. | is desirable, as it provides improved vapour-liquid contact. |
| Answer» C. reduces pressure drop. | |
| 771. |
The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will |
| A. | increase |
| B. | decrease |
| C. | remains same |
| D. | depend on saturated boiling point; may increase or decrease |
| Answer» B. decrease | |
| 772. |
The diffusivity (D) in a binary gas mixture is related to the temperature (T) as |
| A. | D ‚àù T |
| B. | D ‚àù T0.5 |
| C. | D ‚àù T1.5 |
| D. | D ‚àù T2 |
| Answer» D. D ‚àù T2 | |
| 773. |
The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives |
| A. | low pressure drop and high hold up. |
| B. | high pressure drop and low hold up. |
| C. | low pressure drop and low hold up. |
| D. | high pressure drop and high hold up. |
| Answer» D. high pressure drop and high hold up. | |
| 774. |
Use of packed towers for distillation is generally limited to the |
| A. | small sizes. |
| B. | multicomponent distillation. |
| C. | high pressure operation. |
| D. | vacuum distillation. |
| Answer» B. multicomponent distillation. | |
| 775. |
An alkaline solution is used to reduce the concentration of carbon dioxide in a stream from 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is |
| A. | 9.21 |
| B. | 4.605 |
| C. | 100 |
| D. | 0.001 |
| Answer» C. 100 | |
| 776. |
Which of the following equipments is not used for gas dispersion ? |
| A. | Agitated vessels |
| B. | Bubble cap tray towers |
| C. | Perforated sieve tray towers |
| D. | Spray towers |
| Answer» E. | |
| 777. |
Low viscosity absorbent is preferred for reasons of |
| A. | rapid absorption rates and good heat transfer characteristics. |
| B. | improved flooding characteristics. |
| C. | low pressure drop on pumping. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 778. |
Ammonia present in the coke oven gas is removed by washing with |
| A. | caustic solution |
| B. | dilute ammoniacal liquor |
| C. | dilute HCl |
| D. | ethanolamine |
| Answer» C. dilute HCl | |
| 779. |
A minimum boiling azeotrope is exemplified by |
| A. | toluene-benzene |
| B. | acetone-carbon disulphide |
| C. | water-isobutyl alcohol |
| D. | none of these |
| Answer» C. water-isobutyl alcohol | |
| 780. |
Berl saddle made of carbon cannot be used for |
| A. | alkalis |
| B. | SO2 |
| C. | H2SO4 |
| D. | oxidising atmosphere |
| Answer» E. | |
| 781. |
Molarity is defined as the number of gm moles of solute per __________ of solvent. |
| A. | litre |
| B. | kg |
| C. | gm |
| D. | c.c |
| Answer» B. kg | |
| 782. |
High pressure at the bottom of a distillation tower handling heat sensitive materials results in |
| A. | thermal decomposition of bottoms. |
| B. | increased relative volatility. |
| C. | erosion of the tower. |
| D. | very efficient operation. |
| Answer» B. increased relative volatility. | |
| 783. |
A plait point is the point on the solubility curve, where the tie line reduces to a point. What is the number of plait point for a ternery system containing twopairs of partially miscible liquids ? |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 784. |
Which of the following quantities need not be fixed before starting the design of a co-current absorber ? |
| A. | Heat gain or loss |
| B. | Flow rate of entering liquid |
| C. | Flow rate of gas |
| D. | None of these |
| Answer» C. Flow rate of gas | |
| 785. |
Molecular distillation is |
| A. | high temperature distillation |
| B. | for heat-sensitive materials |
| C. | very low pressure distillation |
| D. | both (b) and (c) |
| Answer» E. | |
| 786. |
__________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower. |
| A. | Sherwood |
| B. | Stanton |
| C. | Lewis |
| D. | Peclet |
| Answer» D. Peclet | |
| 787. |
__________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction. |
| A. | Packed |
| B. | Bubble |
| C. | Spray |
| D. | Tray |
| Answer» C. Spray | |
| 788. |
For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will |
| A. | increase |
| B. | decrease |
| C. | remain same |
| D. | data insufficient, can't be predicted |
| Answer» B. decrease | |
| 789. |
The individual mass transfer co-efficients (moles/m2 . s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ? |
| A. | liquid side |
| B. | gas side |
| C. | interfacial |
| D. | both liquid and gas side |
| Answer» C. interfacial | |
| 790. |
The relative volatility of a binary mixture at constant temperature __________ the total pressure. |
| A. | decreases with increase in |
| B. | increases with increase in |
| C. | is independent of |
| D. | none of these |
| Answer» B. increases with increase in | |
| 791. |
Flooding in a column results due to |
| A. | high pressure drop |
| B. | low pressure drop |
| C. | low velocity of the liquid |
| D. | high temperature |
| Answer» B. low pressure drop | |
| 792. |
At equilibrium the concentration of water in vapour phase (C*)in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is |
| A. | 0 |
| B. | 0.2 |
| C. | 0.4 |
| D. | 1 |
| Answer» D. 1 | |
| 793. |
Which is the controlling factor for a drum drier? |
| A. | Diffusion |
| B. | Heat transfer |
| C. | Both (a) and (b) |
| D. | Neither (a) nor (b) |
| Answer» C. Both (a) and (b) | |
| 794. |
Fenske's equation for determining the minimum number of theoretical stages in distillation column holds good, when the |
| A. | relative volatility is reasonably constant. |
| B. | mixture (to be separated) shows negative deviation from ideality. |
| C. | mixture (to be separated) shows positive deviation from ideality. |
| D. | multicomponent distillation is involved. |
| Answer» B. mixture (to be separated) shows negative deviation from ideality. | |
| 795. |
In extraction, as the temperature increases, the area of hetrogeneity (area covered by binodal curve) |
| A. | decreases |
| B. | increases |
| C. | remains unchanged |
| D. | none of these |
| Answer» B. increases | |
| 796. |
If Rm is the minimum reflux ratio, the optimum reflux ratio may be around __________ Rm. |
| A. | 1.2 to 1.5 |
| B. | 2.5 to 3 |
| C. | 3 to 4 |
| D. | 5 |
| Answer» B. 2.5 to 3 | |
| 797. |
The amount of steam required per unit quantity of distillate in case of steam distillation will be reduced by |
| A. | raising the temperature. |
| B. | lowering the total pressure. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 798. |
During drying of a solid, the critical moisture content increases with |
| A. | decreased drying rate |
| B. | increased thickness of the solid |
| C. | increased drying rate |
| D. | both (b) and (c). |
| Answer» E. | |
| 799. |
Large scale drying of wheat is done in a __________ dryer. |
| A. | fluidised bed |
| B. | spouted bed |
| C. | tray |
| D. | vacuum rotary |
| Answer» C. tray | |
| 800. |
Which of the following assumes constant molal vaporisation and overflow ? |
| A. | McCabe-Thiele method |
| B. | Ponchan-Savarit method |
| C. | Enthalpy concentration method |
| D. | Plate absorption column |
| Answer» B. Ponchan-Savarit method | |