MCQOPTIONS
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MCQOPTIONS
This section includes 590 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Prandtl number for water at 20°C is about ________________? |
| A. | 7 |
| B. | 70 |
| C. | 0.7 |
| D. | 150 |
| Answer» B. 70 | |
| 202. |
Powdery materials can be guarded against caking tendency on storage by_________________? |
| A. | Providing irregular grain size |
| B. | Providing minimum percentage of voids |
| C. | Having maximum possible points of contact |
| D. | None of these |
| Answer» E. | |
| 203. |
Powdery materials can be guarded against caking tendency on storage by___________________? |
| A. | Providing irregular grain size |
| B. | Providing minimum percentage of voids |
| C. | Having maximum possible points of contact |
| D. | None of these |
| Answer» E. | |
| 204. |
Positive deviation from Raoult’s law means a mixture whose total pressure is___________________? |
| A. | Greater than that computed for ideality |
| B. | Less than that computed for ideality |
| C. | Less than the sum of the vapour pressure of the components |
| D. | None of these |
| Answer» B. Less than that computed for ideality | |
| 205. |
Pore size of the molecular sieve 5A is ____________________ mm ? |
| A. | 5 |
| B. | 0.5 |
| C. | 0.05 |
| D. | 50 |
| Answer» C. 0.05 | |
| 206. |
Ponchon-Savarit method analyses the fractional equipment based on___________________? |
| A. | Enthalpy balance only |
| B. | Material balance only |
| C. | Both enthalpy and material balances |
| D. | The assumption of constant molal-overflow |
| Answer» D. The assumption of constant molal-overflow | |
| 207. |
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 channelling/flooding |
| D. | None of these |
| Answer» B. Pressure drop in the equipment will be very high | |
| 208. |
Plate efficiency_______________________? |
| A. | Is a function of the mass transfer between liquid and vapour |
| B. | Increases due to foaming |
| C. | Increases due to liquid entrainment |
| D. | Increases due to weeping and dumping of liquid |
| Answer» B. Increases due to foaming | |
| 209. |
Plate efficiency in a distillation column is reduced due to the ______________________ of liquid? |
| A. | Entrainment |
| B. | Foaming |
| C. | Weeping & dumping |
| D. | All A., B. & C. |
| Answer» E. | |
| 210. |
Plate efficiency in a distillation column is reduced due to the ______________ of liquid? |
| A. | Entrainment |
| B. | Foaming |
| C. | Weeping & dumping |
| D. | All A., B. & C. |
| Answer» E. | |
| 211. |
Pick out the wrong statement. Raoult’s law does not apply, when the______________________? |
| A. | Size of component molecules are not equal |
| B. | Attractive forces between like and unlike molecules in the solution are approximately equal |
| C. | Component molecules are non-polar |
| D. | Chemical combination or molecular association between unlike molecules takes place in the formation of solution |
| Answer» D. Chemical combination or molecular association between unlike molecules takes place in the formation of solution | |
| 212. |
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 extend |
| 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 i |
| C. | Rotary dryer is suitable for drying sticky material |
| D. | Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute |
| Answer» D. Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute | |
| 213. |
Pick out the wrong statement pertaining to leaching ? |
| A. | Fine solids cannot be leached in a Pachuca tank |
| B. | Door classifier can be used for leaching of coarse solids |
| C. | Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor |
| D. | Very high temperature is not needed for the leaching of sugar beet |
| Answer» B. Door classifier can be used for leaching of coarse solids | |
| 214. |
Pick out the wrong statement pertaining to the cooling towers ? |
| A. | In case of induced draft cooling tower, the fan is placed at the top of the tower |
| B. | Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air |
| C. | A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low |
| D. | Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature |
| Answer» E. | |
| 215. |
Pick out the wrong statement pertaining to the analogy between equations of heat and mass_________________? |
| 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 | |
| 216. |
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. | |
| 217. |
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 | |
| 218. |
Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.) ? |
| A. | (1 + Ro) = Ro/Ri |
| B. | (1 – Ro) = Ro/Ri |
| C. | (1 + Ri) = Ro/Ri |
| D. | (1 – Ri) = Ro/Ri |
| Answer» B. (1 – Ro) = Ro/Ri | |
| 219. |
Physical absorption is__________________? |
| A. | An irreversible phenomenon |
| B. | A reversible phenomenon |
| C. | Accompanied by evolution of heat |
| D. | Both B. and C. |
| Answer» E. | |
| 220. |
pertaining to the analogy between equations of heat and mass transfer operations ?_x005F_x000D_Pick out the wrong statement |
| 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 | |
| 221. |
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 | |
| 222. |
Percentage saturation is _______________ the relative saturation? |
| A. | Always smaller than |
| B. | Always greater than |
| C. | Not related to |
| D. | None of these |
| Answer» B. Always greater than | |
| 223. |
Penetration theory states that the mass transfer co-coefficient is equal to (where, De is diffusivity and ‘t’ is time) ? |
| A. | (De.t)1/2 |
| B. | (De/t)1/2 |
| C. | (4De/πt)1/2 |
| D. | (4De/t) |
| Answer» D. (4De/t) | |
| 224. |
Penetration theory relates the average mass transfer co-efficient (K) with diffusivity D. as____________________? |
| A. | K ∝D |
| B. | K ∝√D |
| C. | K ∝D1.5 |
| D. | K ∝D2 |
| Answer» C. K ∝D1.5 | |
| 225. |
Penetration model (theory) for mass transfer was enunciated by _____________________? |
| A. | Danckwerts |
| B. | Toor and Marcello |
| C. | Higbie |
| D. | Kissinevskii |
| Answer» D. Kissinevskii | |
| 226. |
Paper industry employs _______________ driers? |
| A. | Cylinder |
| B. | Rotary |
| C. | Spray |
| D. | Fluidised bed |
| Answer» B. Rotary | |
| 227. |
Paper industry employs _____________ driers ? |
| A. | Cylinder |
| B. | Rotary |
| C. | Spray |
| D. | Fluidised bed |
| Answer» B. Rotary | |
| 228. |
Packed column distillation is limited to the column _____________ metres? |
| A. | Height < 6 |
| B. | Diameter < 0.6 |
| C. | Both A. & B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 229. |
Overall efficiency of the distillation column is _____________________? |
| A. | The ratio of number of ideal plates to actual plates |
| B. | The ratio of number of actual plates to ideal plates |
| C. | Same as the Murphree efficiency |
| D. | Always more than the point efficiency |
| Answer» B. The ratio of number of actual plates to ideal plates | |
| 230. |
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 | |
| 231. |
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 | |
| 232. |
Ordinary diffusion process is also called ______________ diffusion? |
| A. | Pressure |
| B. | Thermal |
| C. | Concentration |
| D. | Forced |
| Answer» D. Forced | |
| 233. |
Operating velocity in a packed tower is usually __________________ the flooding velocity ? |
| A. | Half |
| B. | Twice |
| C. | Equal to |
| D. | More than |
| Answer» B. Twice | |
| 234. |
Only small amount of evaporation of water produces large cooling effects because of its___________________? |
| A. | Large latent heat |
| B. | Low viscosity |
| C. | Small latent heat |
| D. | None of these |
| Answer» B. Low viscosity | |
| 235. |
One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect ? |
| A. | The product composition but not the fraction vaporised |
| B. | The product composition as well as the fraction vaporised |
| C. | The fraction vaporised but not the product composition |
| D. | Neither the product composition nor the fraction vaporised |
| Answer» D. Neither the product composition nor the fraction vaporised | |
| 236. |
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 | |
| 237. |
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. | |
| 238. |
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 | |
| 239. |
_______________ 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 | |
| 240. |
(NSh/NRe.NSc) is termed in mass transfer operation as the __________________________? |
| A. | Stanton number |
| B. | Peclet number |
| C. | Thermal diffusivity |
| D. | Momentum diffusivity |
| Answer» B. Peclet number | |
| 241. |
NSc/NPr is called the______________________? |
| A. | Psychrometric ratio |
| B. | Lewis number |
| C. | Sherwood number |
| D. | Stanton number |
| Answer» C. Sherwood number | |
| 242. |
(NRe . NSc) is termed in mass transfer operation as the ______________ number? |
| A. | Stanton |
| B. | Sherwood |
| C. | Peclet |
| D. | None of these |
| Answer» D. None of these | |
| 243. |
Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off _______________ °C? |
| A. | At < 100 |
| B. | At > 210.6 |
| C. | Between 100 and 210 |
| D. | None of these |
| Answer» B. At > 210.6 | |
| 244. |
Most important factor to be considered in the selection of packings for absorbers is the ______________ of packing? |
| A. | Size |
| B. | Durability |
| C. | Porosity |
| D. | Cost |
| Answer» D. Cost | |
| 245. |
Molecular sieves are regenerated by heating to ______________ °C? |
| A. | < 150 |
| B. | 200-330 |
| C. | > 500 |
| D. | > 1000 |
| Answer» C. > 500 | |
| 246. |
Molecular sieves are porous____________________? |
| A. | Alumina |
| B. | Silica |
| C. | Synthetic zeolites crystals/metal alumino-silicates |
| D. | None of these |
| Answer» D. None of these | |
| 247. |
Molecular distillation is_____________________? |
| A. | High temperature distillation |
| B. | For heat-sensitive materials |
| C. | Very low pressure distillation |
| D. | Both B. and C. |
| Answer» E. | |
| 248. |
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 | |
| 249. |
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 | |
| 250. |
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 | |