MCQOPTIONS
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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.
| 2201. |
The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is |
| A. | 2 |
| B. | 0.5 |
| C. | 50 |
| D. | 150 |
| Answer» B. 0.5 | |
| 2202. |
Molecular diffusivity of a liquid |
| A. | increases with temperature. |
| B. | decreases with temperature. |
| C. | may increase or decrease with temperature. |
| D. | is independent of temperature. |
| Answer» B. decreases with temperature. | |
| 2203. |
The wet and 'dry bulb temperature for a vapour-gas mixture are 25 C and 30 C respectively. If the mixture is heated to 45 C at constant pressure, the wet bulb temperature will be __________ C. |
| A. | 25 |
| B. | > 25 |
| C. | < 25 |
| D. | - 25 |
| Answer» C. < 25 | |
| 2204. |
Henry's law states that the |
| A. | partial pressure of a component over a solution is proportional to its mole fraction in the liquid. |
| B. | partial pressure of a component over a solution is proportional to the mole fraction in the vapour. |
| C. | vapour pressure is equal to the product of the mole fraction and total pressure. |
| D. | partial pressure is equal to the product of the mole fraction and total pressure. |
| Answer» B. partial pressure of a component over a solution is proportional to the mole fraction in the vapour. | |
| 2205. |
Mass transfer co-efficient is directly proportional to DAB according to the __________ theory. |
| A. | film |
| B. | penetration |
| C. | surface-renewal |
| D. | none of these |
| Answer» B. penetration | |
| 2206. |
For a binary mixture with low relative volatility, continuous rectification to get pure products will require |
| A. | low reflux ratio |
| B. | less number of trays |
| C. | small cross-section column |
| D. | high reflux ratio |
| Answer» E. | |
| 2207. |
The efficiency of a plate column will be maximum, when the flow is ideal __________ the plate. |
| A. | across |
| B. | above |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 2208. |
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 | |
| 2209. |
Boiling point diagram is not affected by the ambient |
| A. | pressure |
| B. | humidity |
| C. | temperature |
| D. | both (b) and (c) |
| Answer» E. | |
| 2210. |
Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the __________ moisture. |
| A. | bound |
| B. | unbound |
| C. | critical |
| D. | none of these |
| Answer» B. unbound | |
| 2211. |
The dew point of a saturated gas phase equals the __________ temperature. |
| A. | gas |
| B. | room |
| C. | wet bulb |
| D. | none of these |
| Answer» B. room | |
| 2212. |
A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process ? |
| A. | Flow rate of inlet air |
| B. | Relative humidity of outlet air |
| C. | Humidity of inlet air |
| D. | Temperature of the solid |
| Answer» E. | |
| 2213. |
In case of liquid-liquid binary diffusion, diffusivity of one constituent into another is not dependent on the |
| A. | temperature and pressure |
| B. | concentration |
| C. | nature of the constituents |
| D. | none of these |
| Answer» E. | |
| 2214. |
For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because |
| A. | water has a high latent heat of evaporation. |
| B. | Lewis number is close to unity. |
| C. | they are always equal under all circumstances. |
| D. | solubility of the components of air in water is very small. |
| Answer» B. Lewis number is close to unity. | |
| 2215. |
Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around __________ inches. |
| A. | 5 |
| B. | 30 |
| C. | 60 |
| D. | 100 |
| Answer» C. 60 | |
| 2216. |
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. | |
| 2217. |
Flooding results in |
| A. | high tray efficiency |
| B. | low tray efficiency |
| C. | high gas velocity |
| D. | good contact between the fluids |
| Answer» C. high gas velocity | |
| 2218. |
In an operating distillation column, the |
| A. | vapors and liquids are at their dew point and bubble point respectively |
| B. | driving force for the liquid flow is its specific weight. |
| C. | driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column. |
| D. | highest temperature is encountered at the top of the column. |
| Answer» D. highest temperature is encountered at the top of the column. | |
| 2219. |
The dimension of diffusivity is same as that of the |
| A. | density |
| B. | molal concentration |
| C. | kinematic viscosity |
| D. | velocity head |
| Answer» D. velocity head | |
| 2220. |
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 | |
| 2221. |
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 | |
| 2222. |
Mechanism of moisture removal in case of freeze drying of food stuff is by |
| A. | evaporation |
| B. | sublimation |
| C. | dehydration |
| D. | adsorption |
| Answer» C. dehydration | |
| 2223. |
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 | |
| 2224. |
Which is not concerned directly with mass transfer ? |
| A. | Schmidt number |
| B. | Sherwood number |
| C. | Lewis relationship |
| D. | Froude number |
| Answer» E. | |
| 2225. |
__________ 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 | |
| 2226. |
Rotary dryers cannot handle __________ materials. |
| A. | free flowing |
| B. | dry |
| C. | sticky |
| D. | grannular |
| Answer» D. grannular | |
| 2227. |
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 | |
| 2228. |
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. | |
| 2229. |
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. | |
| 2230. |
The solvent used in liquid-liquid extraction should have __________ less than one. |
| A. | selectivity |
| B. | distribution co-efficient |
| C. | both (a) and (b) |
| D. | neither (a) nor (b). |
| Answer» E. | |
| 2231. |
The suitable evaporator for concentration of foaming liquids is a __________ evaporator. |
| A. | long tube |
| B. | short tube |
| C. | vacuum |
| D. | falling film |
| Answer» B. short tube | |
| 2232. |
If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are |
| A. | straight |
| B. | parallel |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 2233. |
Which of the following operations does not involve leaching ? |
| A. | Dissolving gold from ores. |
| B. | Dissolving pharmaceutical products from bark or roots. |
| C. | Dissolving sugar from the cells of the beet. |
| D. | Removing nicotine from its water solution by kerosene. |
| Answer» E. | |
| 2234. |
The recovery of pencillin from the acidified fermentation broth is done by |
| A. | distillation |
| B. | evaporation |
| C. | absorption |
| D. | liquid extraction |
| Answer» E. | |
| 2235. |
The relative volatility of a binary mixture at the azeotropic composition is |
| A. | 1 |
| B. | > 1 |
| C. | 0 |
| D. | |
| Answer» B. > 1 | |
| 2236. |
Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when |
| A. | only vapor phase follows Raoult's law. |
| B. | only liquid phase obeys Dalton's law. |
| C. | liquid phase obeys Dalton's law and vapor phase obeys Raoult's law. |
| D. | Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law. |
| Answer» E. | |
| 2237. |
Unit operation involved in the prilling of urea is |
| A. | evaporation |
| B. | drying |
| C. | crystallisation |
| D. | both (b) and (c) |
| Answer» E. | |
| 2238. |
Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature. |
| A. | less than |
| B. | more than |
| C. | equal to |
| D. | either (o) or (b); depends on the solid |
| Answer» B. more than | |
| 2239. |
Lewis number (Le) is |
| A. | Sc x Pr |
| B. | Pr x St |
| C. | Sh x Pr |
| D. | St x Sh |
| Answer» B. Pr x St | |
| 2240. |
Pore size of the molecular seive 5A is __________ mm. |
| A. | 5 |
| B. | 0.5 |
| C. | 0.05 |
| D. | 50 |
| Answer» C. 0.05 | |
| 2241. |
Swenson-Walker crystalliser is a __________ unit |
| A. | continuous |
| B. | batch |
| C. | semi-batch |
| D. | cooling (adiabatic)-cum-evaporation |
| Answer» B. batch | |
| 2242. |
According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility ( AB = 2) does not change appreciably in the coloumn. |
| A. | 5 |
| B. | 9 |
| C. | 12 |
| D. | 28 |
| Answer» D. 28 | |
| 2243. |
Absorption (liquid-gas system) with evolution of heat as compared to isothermal absorption results in |
| A. | decreased solute solubility. |
| B. | large minimum liquid to gas (L/G) ratio. |
| C. | large number of trays. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 2244. |
With increase in temperature, the mutual solubility of two liquids |
| A. | increases |
| B. | decreases |
| C. | remains unchanged |
| D. | decreases exponentially |
| Answer» B. decreases | |
| 2245. |
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 | |
| 2246. |
Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty ? |
| A. | Grid tray tower |
| B. | Perforated tray tower |
| C. | Wetted wall tower |
| D. | Bubble cap tower |
| Answer» E. | |
| 2247. |
A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture? |
| A. | The mixture exhibits an azeotrope at 101.3 kPa. |
| B. | The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10. |
| C. | The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10. |
| D. | The mixture contain optical isomers. |
| Answer» B. The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10. | |
| 2248. |
Unsaturated air (with dry bulb temperature and dew point being 35 C and 18 C respectively) is passed through a water spray chamber maintained at 15 C. The air will be cooled |
| A. | and humidified. |
| B. | and dehumidified with increase in wet bulb temperature. |
| C. | at the same relative humidity. |
| D. | and dehumidified with decrease in wet bulb temperature. |
| Answer» E. | |
| 2249. |
The process employing desorption of the absorbed solute by a solvent is called |
| A. | elution |
| B. | osmosis |
| C. | reverse osmosis |
| D. | sublimation |
| Answer» B. osmosis | |
| 2250. |
Dry bulb temperature of the gas is __________ the wet bulb temperature. |
| A. | less than |
| B. | more than |
| C. | equal to |
| D. | none of these |
| Answer» C. equal to | |