MCQOPTIONS
Saved Bookmarks
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.
| 651. |
In a packed bed absorption column, the channelling will be noted by the |
| A. | increase in flow rate. |
| B. | sharp drop in pressure drop. |
| C. | sharp rise in pressure drop. |
| D. | none of these. |
| Answer» C. sharp rise in pressure drop. | |
| 652. |
Molecular diffusion is caused by the |
| A. | transfer of molecules from low concentration to high concentration region. |
| B. | thermal energy of the molecules. |
| C. | activation energy of the molecules. |
| D. | potential energy of the molecules. |
| Answer» C. activation energy of the molecules. | |
| 653. |
Heat in BTU necessary to increase the temperature of 1 lb of gas and its accompanying vapour by 1°F is called the$ |
| A. | latent heat |
| B. | humid heat |
| C. | specific heat |
| D. | sensible heat |
| Answer» D. sensible heat | |
| 654. |
Diffusivity in concentrated solutions differs from that in dilute solutions, because of the changes in |
| A. | viscosity with concentration. |
| B. | degree of ideality of the solution. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 655. |
The cooling effect in a cooling tower can not be increased by |
| A. | increasing the air velocity over the wet surfaces. |
| B. | reducing the humidity of entering air. |
| C. | lowering the barometric pressure. |
| D. | none of these. |
| Answer» E. | |
| 656. |
Can a cooling tower cool water below the wet bulb temperature of inlet air ? |
| A. | yes |
| B. | no |
| C. | yes ; but height of cooling tower will be prohibitively high. |
| D. | yes ; but the air flow rate should be excessively high. |
| Answer» C. yes ; but height of cooling tower will be prohibitively high. | |
| 657. |
A good solvent used for absorption should not have very high |
| A. | viscosity |
| B. | vapor pressure |
| C. | freezing point |
| D. | all (a), (b) & (c) |
| Answer» E. | |
| 658. |
Absorption factor is defined as (where, S1 = slope of the operating line S2 = slope of the equilibrium curve) |
| A. | S2/S1 |
| B. | S1/S2 |
| C. | S1 - S2 |
| D. | S1 x S2 |
| Answer» C. S1 - S2 | |
| 659. |
The difference of wet bulb temperature and adiabatic saturation temperature of unsaturated mixture of any system is |
| A. | #NAME? |
| B. | #NAME? |
| C. | zero |
| D. | none of these |
| Answer» B. #NAME? | |
| 660. |
__________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids. |
| A. | Watted wall |
| B. | Packed |
| C. | Plate |
| D. | Spray |
| Answer» D. Spray | |
| 661. |
As the reflux ratio, in a continuous counter-current extraction is increased, the number of stages |
| A. | increase |
| B. | decrease |
| C. | remain unchanged |
| D. | can either increase or decrease, depends on the system |
| Answer» C. remain unchanged | |
| 662. |
The rate of solid-liquid extraction is limited by the |
| A. | phase change of the solute as it dissolves in the solvent. |
| B. | diffusion of the solute through the solvent in the pores to the outside of the particle. |
| C. | diffusion of the solute from the solution in contact with the particle to the main bulk of the solution. |
| D. | all 'a', 'b' & 'c'. |
| Answer» E. | |
| 663. |
For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as |
| A. | Re0.33 |
| B. | Re0.53 |
| C. | Re0.83 |
| D. | Re |
| Answer» D. Re | |
| 664. |
For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. |
| A. | unsaturated surface |
| B. | constant rate |
| C. | both (a) and (b) |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 665. |
The Kundsen diffusivity is proportional to (where, T = absolute temperature) |
| A. | T |
| B. | T2 |
| C. | T |
| D. | T4 |
| Answer» B. T2 | |
| 666. |
In distillation, overhead product contains |
| A. | only one component |
| B. | two components |
| C. | any number of components |
| D. | only saturated liquid |
| Answer» D. only saturated liquid | |
| 667. |
Heat load in a cooling tower |
| A. | means the amount of heat thrown away (KCal/hr.) by the cooling tower. |
| B. | is equal to the number of kg, of water circulated times the cooling range. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 668. |
At minimum reflux ratio for a given separation |
| A. | number of plates is zero. |
| B. | number of plates is infinity. |
| C. | minimum number of the theoretical plates is required. |
| D. | separation is most efficient. |
| Answer» C. minimum number of the theoretical plates is required. | |
| 669. |
A distillation column separates 10000 kg/hr of a benzene-toluene mixture as shown in the figure below : In the figure xF, xD and xW represent the weight fraction of benzene in the feed, distillate and residue respectively. The reflux ratio is |
| A. | 0.5 |
| B. | 0.6 |
| C. | 1 |
| D. | 2 |
| Answer» C. 1 | |
| 670. |
Physical absorption is |
| A. | an irreversible phenomenon. |
| B. | a reversible phenomenon. |
| C. | accompanied by evolution of heat. |
| D. | both (b) and (c) |
| Answer» E. | |
| 671. |
Equilibrium-moisture curves of different solids |
| A. | are different |
| B. | are same |
| C. | depend on the humidity of the gas |
| D. | none of these |
| Answer» B. are same | |
| 672. |
A packed tower compared to a plate tower for a particular mass transfer operation |
| A. | incurs smaller pressure drop. |
| B. | allows installation of cooling coils. |
| C. | is less costly when built in large sizes/diameters. |
| D. | is more suitable, if suspended solids are present in fluid streams. |
| Answer» B. allows installation of cooling coils. | |
| 673. |
When the gas to be dissolved in liquid is a/an __________ then normally co-current adsorber are used. |
| A. | mixture of two gases |
| B. | pure gas |
| C. | ideal gas |
| D. | sparingly soluble gas |
| Answer» C. ideal gas | |
| 674. |
Reverse osmosis is also called |
| A. | dialysis |
| B. | electrodilysis |
| C. | diffusion |
| D. | ultrafiltration. |
| Answer» E. | |
| 675. |
Schimdt number and Lewis number for pure air at atmospheric conditions are respectively |
| A. | < 1 and ≈ 1 |
| B. | 1 and 0 |
| C. | >1 and ≈ 1 |
| D. | 0 and ≈ 1 |
| Answer» B. 1 and 0 | |
| 676. |
Removal of __________ exemplifies an adsorption unit operation. |
| A. | uranium from its ore |
| B. | water from petrol |
| C. | ammonia from coke oven gas |
| D. | mustard oil from mustard seed |
| Answer» C. ammonia from coke oven gas | |
| 677. |
For contacting a highly soluble gas with a liquid |
| A. | bubble the gas through liquid. |
| B. | spray the liquid on gas stream. |
| C. | either (a) or (b) would suffice. |
| D. | none of these. |
| Answer» B. spray the liquid on gas stream. | |
| 678. |
The equilibrium liquid composition compared to the vapor composition in case of azeotropic mixture is |
| A. | more |
| B. | less |
| C. | same |
| D. | either more or less; depends on the system |
| Answer» D. either more or less; depends on the system | |
| 679. |
A coalescer in a mixer-settler liquid-liquid extraction coloumn |
| A. | comprises of thin bed of substances of extended surface having high porosity. |
| B. | helps in increasing the bubble size entering the settler. |
| C. | helps in increasing the settling rate of the bubbles. |
| D. | all 'a', 'b', & 'c'. |
| Answer» E. | |
| 680. |
Steam distillation is not recommended to be used, if the |
| A. | azeotropic mixture is to be separated and the final product is miscible with water. |
| B. | liquids decompose, if distilled directly at atmospheric pressure. |
| C. | material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature. |
| D. | material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature. |
| Answer» B. liquids decompose, if distilled directly at atmospheric pressure. | |
| 681. |
With increase in the concentration of the adsorbate, the integral heat of adsorption |
| A. | increases. |
| B. | decreases. |
| C. | remains unchanged. |
| D. | may increase or decrease ; depends on the type of adsorbate. |
| Answer» C. remains unchanged. | |
| 682. |
The relation, Sc = Pr = 1, is valid, when the mechanism of __________ ansfer is same. |
| A. | heat and mass |
| B. | mass and momentum |
| C. | heat and momentum |
| D. | heat, momentum and mass |
| Answer» B. mass and momentum | |
| 683. |
Which of the following same diameter columns gives lowest pressure drop per unit height ? |
| A. | Bubble-cap column |
| B. | Sieve-plate column |
| C. | Packed column (stacked) |
| D. | Randomly packed column |
| Answer» D. Randomly packed column | |
| 684. |
In batch distillation with constant reflux, overhead product composition __________ with time. |
| A. | increases |
| B. | decreases |
| C. | does not vary |
| D. | may increase on decrease, depends on the system. |
| Answer» C. does not vary | |
| 685. |
Which of the following is directly concerned with psychrometry ? |
| A. | Lewis reltionship |
| B. | Galileo number |
| C. | Weber number |
| D. | Dean number |
| Answer» B. Galileo number | |
| 686. |
Extraction of coffee from its seed is done by |
| A. | liquid-liquid extraction. |
| B. | leaching. |
| C. | extractive distillation. |
| D. | steam distillation. |
| Answer» C. extractive distillation. | |
| 687. |
The operating line for an absorber is curved, when plotted in terms of |
| A. | mole fractions |
| B. | mole ratios |
| C. | partial pressure |
| D. | mass fractions |
| Answer» D. mass fractions | |
| 688. |
Stefan's law describes the mass transfer by |
| A. | diffusion |
| B. | bulk flow |
| C. | both 'a' & 'b' |
| D. | neither 'a' nor 'b' |
| Answer» D. neither 'a' nor 'b' | |
| 689. |
For absorbing a sparingly soluble gas in a liquid, the |
| A. | gas side co-efficient should be increased. |
| B. | liquid side coefficient should be increased. |
| C. | gas side co-efficient should be decreased. |
| D. | liquid side co-efficient should be decreased. |
| Answer» C. gas side co-efficient should be decreased. | |
| 690. |
Which is not concerned directly with mass transfer ? |
| A. | Schmidt number |
| B. | Sherwood number |
| C. | Lewis relationship |
| D. | Froude number |
| Answer» E. | |
| 691. |
Raschig ring made of procelain cannot be used for treating concentrated |
| A. | hydrochloric acid |
| B. | nitric acid |
| C. | alkalis |
| D. | sulphuric acid |
| Answer» D. sulphuric acid | |
| 692. |
Humid volume is the total volume in m3 of 1 kg of |
| A. | vapour laden gas at 1 atm. and room temperature. |
| B. | gas plus its accompanying vapour at 1 atm. and room temperature. |
| C. | gas plus its accompanying vapour at 1 atm. and gas temperature. |
| D. | vapour laden gas at 1 atm. and gas temperature. |
| Answer» D. vapour laden gas at 1 atm. and gas temperature. | |
| 693. |
The percentage humidity is less than the relative humidity only at __________ percent humidity. |
| A. | zero |
| B. | hundred |
| C. | both zero and hundred |
| D. | none of these |
| Answer» D. none of these | |
| 694. |
The boiling points of pure components of a binary system __________ with increase in total pressure of the system. |
| A. | decreases |
| B. | increases |
| C. | remains unchanged |
| D. | may increase or decrease, depends on the system. |
| Answer» C. remains unchanged | |
| 695. |
The apex of an equilateral-triangular coordinate (in ternary liquid system) represents a/an |
| A. | pure component |
| B. | binary mixture |
| C. | ternary mixture |
| D. | insoluble binary system |
| Answer» B. binary mixture | |
| 696. |
Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer. |
| A. | rotary |
| B. | vacuum |
| C. | tunnel |
| D. | tray |
| Answer» B. vacuum | |
| 697. |
Inside the distillation column, the |
| A. | driving force for the vapour flow is the pressure drop. |
| B. | liquids are not always at their bubble points. |
| C. | pressure increases gradually from bottom to the top of the column. |
| D. | none of these |
| Answer» B. liquids are not always at their bubble points. | |
| 698. |
For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of __________ microns (1 mm = 1000 microns). |
| A. | 43586 |
| B. | 22190 |
| C. | 200-300 |
| D. | > 500 |
| Answer» C. 200-300 | |
| 699. |
At 750°K and 1 atm, the approximate value of Schmidt number for air is$ |
| A. | 0.01 |
| B. | 0.1 |
| C. | 1 |
| D. | 10 |
| Answer» C. 1 | |
| 700. |
Separation of __________ employs gaseous diffusion process. |
| A. | N2 and O2 from air |
| B. | isotopes of uranium |
| C. | isotopes of helium |
| D. | SO2 and air |
| Answer» C. isotopes of helium | |