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MCQOPTIONS
This section includes 8247 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1551. |
In paper industry, paper is dried in a __________ dryer. |
| A. | tunnel |
| B. | heated cylinder |
| C. | conveyor |
| D. | festoon |
| Answer» C. conveyor | |
| 1552. |
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 | |
| 1553. |
The mass transfer co-efficient for a solid sphere of radius 'a' dissolving in a large volume of quiescent liquid, in which D is the diffusivity of solute, is |
| A. | D/a |
| B. | D/2a |
| C. | proportional to |
| D. | <span class="root">D</span> |
| E. | dependent on the Reynolds number |
| Answer» E. dependent on the Reynolds number | |
| 1554. |
Pick out the wrong statement. Generally for physical adsorption, a gas of |
| A. | higher molecular weight is adsorbed in preference to a gas of low molecular weight. |
| B. | high critical temperature is adsorbed in preference to a gas of low critical temperature. |
| C. | low volatility is adsorbed in preference to a gas of high volatility. |
| D. | none of these. |
| Answer» E. | |
| 1555. |
In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in |
| A. | reducing the axial mixing. |
| B. | increasing the rate of extraction. |
| C. | maintaining the concentration difference between the two phases. |
| D. | all 'a', 'b' & 'c'. |
| Answer» E. | |
| 1556. |
In a vapor-liquid contacting equipment, the overall gas phase mass transfer co-efficient (M.T.C), KG is related to individual co-efficients (KG and KL) as |
| A. | <img src="/_files/images/chemical-engineering/mass-transfer/316-486-1.png"> |
| B. | <img src="/_files/images/chemical-engineering/mass-transfer/316-486-2.png"> |
| C. | <img src="/_files/images/chemical-engineering/mass-transfer/316-486-3.png"> |
| D. | <img src="/_files/images/chemical-engineering/mass-transfer/316-486-4.png"> |
| Answer» C. <img src="/_files/images/chemical-engineering/mass-transfer/316-486-3.png"> | |
| 1557. |
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) |
| A. | increases pressure drop, increases surface area. |
| B. | increases pressure drop, decreases surface area. |
| C. | decreases pressure drop, increases surface area. |
| D. | decreases pressure drop, decreases surface area. |
| Answer» D. decreases pressure drop, decreases surface area. | |
| 1558. |
Critical humidity of a solid salt means the humidity |
| A. | above which it will always become damp. |
| B. | below which it will always stay dry. |
| C. | both (a) and (b). |
| D. | above Which it will always become dry and below which it will always stay damp. |
| Answer» D. above Which it will always become dry and below which it will always stay damp. | |
| 1559. |
The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are |
| A. | parallel |
| B. | straight |
| C. | both parallel and straight |
| D. | neither parallel nor straight |
| Answer» D. neither parallel nor straight | |
| 1560. |
Flights in a rotary dryer are provided to |
| A. | lift and shower the solids thus exposing it thoroughly to the drying action of the gas. |
| B. | reduce the residence time of solid. |
| C. | increase the residence time of the solid. |
| D. | none of these. |
| Answer» B. reduce the residence time of solid. | |
| 1561. |
If f = moles of vapour present per mole of feed, then the slope of feed line is (Mcabe-Thiele method) |
| A. | <img src="/_files/images/chemical-engineering/mass-transfer/287-97-1.png"> |
| B. | <img src="/_files/images/chemical-engineering/mass-transfer/287-97-2.png"> |
| C. | <img src="/_files/images/chemical-engineering/mass-transfer/287-97-3.png"> |
| D. | <img src="/_files/images/chemical-engineering/mass-transfer/287-97-4.png"> |
| Answer» D. <img src="/_files/images/chemical-engineering/mass-transfer/287-97-4.png"> | |
| 1562. |
If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that |
| A. | the system comprises of partially mis-cible liquids. |
| B. | the system comprises of miscible liquids. |
| C. | the system comprises of an azeotrope. |
| D. | on heating, a vapor phase will appear ; while on cooling, a solid phase will appear. |
| Answer» E. | |
| 1563. |
The rate of mass transfer is not dependent upon the |
| A. | degree of dispersion of one fluid in the other. |
| B. | interfacial surface exposed between the phases. |
| C. | both (a) & (b). |
| D. | none of these. |
| Answer» E. | |
| 1564. |
Ordinary diffusion process is also called __________ diffusion. |
| A. | pressure |
| B. | thermal |
| C. | concentration |
| D. | forced. |
| Answer» D. forced. | |
| 1565. |
Pick out the wrong statement pertaining to the rotary dryer. |
| A. | Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it down through the current of hot air/gases. It extends from the wall to a distance which is about 8-12% of the inside diameter of shell. |
| B. | Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at any instant. The best performance for rotary drier is obtained, when the hold up is in the range of 0.05 to 0.15. |
| C. | Rotary dryer is suitable for drying sticky material. |
| D. | Recommended peripherial speed of a rotary drier is in the range of 10 to 30 metres/minute. |
| Answer» D. Recommended peripherial speed of a rotary drier is in the range of 10 to 30 metres/minute. | |
| 1566. |
__________ diffusion is used for separating the isotopes of methane. |
| A. | Thermal |
| B. | Pressure |
| C. | Concentration |
| D. | Force |
| Answer» B. Pressure | |
| 1567. |
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 | |
| 1568. |
Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. |
| A. | wetted wall |
| B. | bubble cap |
| C. | perforated tray |
| D. | packed |
| Answer» B. bubble cap | |
| 1569. |
Pick out the system with minimum boiling azeotrope at 1 atm. |
| A. | benzene-toluene |
| B. | ethyl alcohol-water |
| C. | hydrochloric acid-water |
| D. | all (a), (b) and (c) |
| Answer» C. hydrochloric acid-water | |
| 1570. |
Free flowing granular materials can be best dried in a __________ drier. |
| A. | rotary |
| B. | cylinder |
| C. | drun |
| D. | freeze |
| Answer» B. cylinder | |
| 1571. |
In McCabe-Thiele method, at infinite reflux ratio |
| A. | the overhead product is minimum. |
| B. | both the operating lines coincide with diagonal. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» B. both the operating lines coincide with diagonal. | |
| 1572. |
In case of an ideal solution, the total vapor pressure varies __________ with the composition expressed as mole fraction, |
| A. | inversely |
| B. | linearly |
| C. | exponentially |
| D. | none of these |
| Answer» C. exponentially | |
| 1573. |
In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of |
| A. | area between operating line and 45 diagonal x-y diagram. |
| B. | condenser and reboiler surfaces. |
| C. | tower cross-section. |
| D. | none of these. |
| Answer» B. condenser and reboiler surfaces. | |
| 1574. |
Wetted wall tower experiment determines the |
| A. | molal diffusivity. |
| B. | volumetric co-efficient. |
| C. | mass transfer co-efficient. |
| D. | none of these. |
| Answer» D. none of these. | |
| 1575. |
With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | may increase or decrease ; depends on individual design |
| Answer» B. decreases | |
| 1576. |
Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the |
| A. | packing may be crushed due to thermal expansion/contraction of the components of the equipments. |
| B. | pressure drop in the equipment will be . very high. |
| C. | viscosity variation of the fluids may cause channeling/flooding. |
| D. | none of these. |
| Answer» B. pressure drop in the equipment will be . very high. | |
| 1577. |
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. | |
| 1578. |
When the liquid phase and vapour phase of a binary system obeys Raoult's and Dalton's law respectively, the relative volatility is the ratio of |
| A. | vapour pressure of component A to that of component B. |
| B. | vapour pressure of component A to the total pressure. |
| C. | vapour pressure of component A to the partial pressure of A. |
| D. | partial pressure of component A to the total pressure. |
| Answer» B. vapour pressure of component A to the total pressure. | |
| 1579. |
The operation involved when the soluble material is largely on the surface of an insoluble solid and is merely washed off by the solvent is called |
| A. | decoction |
| B. | percolation |
| C. | elutriation or elution |
| D. | none of these |
| Answer» D. none of these | |
| 1580. |
In the constant rate period of the rate of drying curve for batch drying, |
| A. | cracks develop on the surface of the solid. |
| B. | rate of drying decreases abruptly. |
| C. | surface evaporation of unbound moisture occurs. |
| D. | none of these. |
| Answer» D. none of these. | |
| 1581. |
It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The equilibrium moisture content of the solid is 5%). |
| A. | 15 min |
| B. | 51 min |
| C. | 71 min |
| D. | 94 min |
| Answer» D. 94 min | |
| 1582. |
If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent. |
| A. | 100 |
| B. | > 100 |
| C. | < 100 |
| D. | none of these |
| Answer» C. < 100 | |
| 1583. |
Compound A is extracted from a solution of A + B into a pure solvent S. A Co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 moles of B/hr.m2 and the solvent flow, rate is 400 moles of S/m2. hr. The equilibrium data is represented by Y = 3X2 , where Y is in moles of a A/moles of B and X is in moles A/moles of S. The maximum percentage extraction achieved in the unit is |
| A. | 25% |
| B. | 50% |
| C. | 70% |
| D. | 90% |
| Answer» C. 70% | |
| 1584. |
Raoult's law is applicable to the |
| A. | ideal solutions |
| B. | real solutions |
| C. | mixture of water and alcohol |
| D. | non-ideal gases |
| Answer» B. real solutions | |
| 1585. |
Weeping in a distillation column |
| A. | increases tray efficiency. |
| B. | provides large interfacial surface for mass transfer. |
| C. | results due to very high gas velocity. |
| D. | results due to very low gas velocity. |
| Answer» E. | |
| 1586. |
On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in |
| A. | greater degree of separation with a fixed number of trays |
| B. | increased reboiler load |
| C. | increased reflux ratio |
| D. | None of these. |
| Answer» D. None of these. | |
| 1587. |
__________ 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 | |
| 1588. |
Deairation (removal of O2) of water is done by |
| A. | rectification |
| B. | absorption |
| C. | ion-exchange |
| D. | adsorption |
| Answer» D. adsorption | |
| 1589. |
Make up water is supplied during cooling tower operation to compensate for water losses due to |
| A. | evaporation |
| B. | blowdown |
| C. | entrainment |
| D. | all (a), (b)&(c) |
| Answer» E. | |
| 1590. |
Removal of hydrogen from coke oven gas |
| A. | increases its calorific value. |
| B. | decreases its calorific value. |
| C. | does not alter its calorific value. |
| D. | is not possible on commerical scale. |
| Answer» B. decreases its calorific value. | |
| 1591. |
If oxygen content in the flue gas rises too high, fuel is being wasted by |
| A. | incomplete combustion. |
| B. | dry gas/stack gas loss. |
| C. | moisture loss. |
| D. | none of these. |
| Answer» C. moisture loss. | |
| 1592. |
Increase in ash content of blast furnace coke |
| A. | reduces its consumption in the furnace. |
| B. | increases its consumption in the furnace. |
| C. | does not affect its consumption in the furnace. |
| D. | decreases its hardness and abrasion resistance. |
| Answer» C. does not affect its consumption in the furnace. | |
| 1593. |
Safe condition for storage of high V.M. bituminous coal is that |
| A. | height of the coal heap should be < 3 metres. |
| B. | maximum 200 tons should be stored in a heap. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 1594. |
Ignition temperature of a fuel in air is __________ that in pure oxygen. |
| A. | more than |
| B. | less than |
| C. | equal to |
| D. | either more or less; depends on the type of fuel |
| Answer» B. less than | |
| 1595. |
Which of the following is called "blue gas" ? |
| A. | coke oven gas |
| B. | water gas |
| C. | natural gas |
| D. | producer gas |
| Answer» C. natural gas | |
| 1596. |
Caking index of a coal is a measure of its |
| A. | abradability |
| B. | reactivity |
| C. | agglutinating (binding) properties |
| D. | porosity |
| Answer» D. porosity | |
| 1597. |
Calorific value of furnace oil is about __________ Kcal/kg. |
| A. | 10000 |
| B. | 15000 |
| C. | 5000 |
| D. | 20000 |
| Answer» B. 15000 | |
| 1598. |
Quantity of coke produced from metallurgical coal may be around __________ percent. |
| A. | 30 |
| B. | 50 |
| C. | 75 |
| D. | 95 |
| Answer» D. 95 | |
| 1599. |
Coal is heated in presence of air to a temperature of about __________ C, while determining its ash content for proximate analysis. |
| A. | 500 |
| B. | 750 |
| C. | 950 |
| D. | 1100 |
| Answer» C. 950 | |
| 1600. |
Out of the following fuels, the difference between gross and net calorific value will be minimum in case of |
| A. | coke oven gas |
| B. | water gas |
| C. | natural gas |
| D. | blast furnace gas |
| Answer» E. | |