MCQOPTIONS
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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.
| 101. |
Mass transfer co-efficient is directly proportional to Dᴀʙ^0.5, according to __________ theory. |
| A. | penetration |
| B. | surface renewal |
| C. | film |
| D. | none of these |
| Answer» B. surface renewal | |
| 102. |
Mass transfer co-efficient varies as Dᴀʙ^0.5, according to the __________ theory. |
| A. | film |
| B. | surface renewal |
| C. | penetration |
| D. | none of these |
| Answer» C. penetration | |
| 103. |
The value of Nᴀ/(Nᴀ + Nʙ) for steady state molecular diffusion of gas 'A' through non-diffusing gas 'B' is |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» B. ∞ | |
| 104. |
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 (αᴀʙ = 2) does not change appreciably in the coloumn. |
| A. | 5 |
| B. | 9 |
| C. | 12 |
| D. | 28 |
| Answer» D. 28 | |
| 105. |
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 two pairs of partially miscible liquids ? |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 106. |
Which of the following is a suitable absorbent for removal of H₂S from natural gas ? |
| A. | Vetrocoke solution |
| B. | Monoethanol amine (MEA) |
| C. | Dilute |
| D. | Hot water |
| Answer» C. Dilute | |
| 107. |
Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure.Nitrobenzene will distill off __________ °C. |
| A. | at < 100 |
| B. | at > 210.6 |
| C. | between 100 and 210 |
| D. | none of these |
| Answer» B. at > 210.6 | |
| 108. |
The value of Nᴀ/(Nᴀ + Nʙ), for steady state equimolal counter diffusion of two gases 'A' and 'B' is |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» C. 0.5 | |
| 109. |
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 | |
| 110. |
The diffusivity, Dᴀʙ (for component A diffusing in B) is equal to the diffusivity Dʙᴀ (for component B diffusing in A) for a binary mixture of |
| A. | Newtonion liquids |
| B. | non-Newtonion liquids |
| C. | ideal gases |
| D. | real gases |
| Answer» D. real gases | |
| 111. |
For the case of flow of air past a wet bulb thermometer (air water vapour system), the approximate value of H₂/ky.Cz is around |
| A. | 0.60 |
| B. | 0.24 |
| C. | 1 |
| D. | 0.72 |
| Answer» D. 0.72 | |
| 112. |
Component A is diffusing in a medium B. The flux Nᴀ relative to a stationary point is equal to the flux due to molecular difusion, if |
| A. | mass transfer is accompanied by reaction. |
| B. | diffusion of A is in stagnant medium B. |
| C. | molecular mean free path is high. |
| D. | there is equimolar counter diffusion. |
| Answer» E. | |
| 113. |
Which of the following liquid temperature (T) Vs. vapor-gas mixture enthalpy (H) diagram is valid for humidification operation? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 114. |
The following equation is for |
| A. | steady state equimolar counter diffusion |
| B. | Fick's first law of diffusion |
| C. | steady state diffusion for stagnant case |
| D. | liquid M.T.C. by penetration theory |
| Answer» B. Fick's first law of diffusion | |
| 115. |
Which of the following is the correct ternery diagram for liquid-liquid extraction system comprising of one pair partly soluble (e.g. water-benzene-acetic acid in which A-diluent, B - solvent and C - solute)? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 116. |
The following expression is |
| A. | differential distillation equation |
| B. | for NtoG in absorption for dilute mixture |
| C. | slope of q-line in McCabe-Thiele method |
| D. | for relative volatility |
| Answer» B. for NtoG in absorption for dilute mixture | |
| 117. |
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. | 1.0 |
| D. | 2.0 |
| Answer» C. 1.0 | |
| 118. |
Which of the following is not a unit of mass transfer co-efficient ? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 119. |
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. | 0.0 |
| B. | 0.2 |
| C. | 0.4 |
| D. | 1.0 |
| Answer» D. 1.0 | |
| 120. |
If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively |
| A. | A |
| B. | B |
| C. | C |
| D. | None of these |
| Answer» C. C | |
| 121. |
Pick out the wrong statement |
| A. | A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity. |
| B. | When water is cooled from 80 to 70°C by exposure to the air with a wet bulb temperature of 60°C, then both the approach & the range would be 10°C. |
| C. | For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature & adiabatic cooling lines are the same. |
| D. | Relative saturation of unsaturated mixture of water vapor & air can not be increased by either reducing the mixture temperature or by increasing the total pressure. |
| Answer» E. | |
| 122. |
Mass transfer co-efficient is directly proportional to Dᴀʙ according to the __________ theory. |
| A. | film |
| B. | penetration |
| C. | surface-renewal |
| D. | none of these |
| Answer» B. penetration | |
| 123. |
An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored: (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) |
| A. | less number of trays are required. |
| B. | composition of the residue remains unchanged. |
| C. | more number of trays are required but the residue composition remains unchanged. |
| D. | more number of trays are required and the residue composition is more dilute in methanol. |
| Answer» B. composition of the residue remains unchanged. | |
| 124. |
Which of the following T-H diagram is valid for dehumidification operation ? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 125. |
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. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 126. |
In gas-liquid contact operation, the number of ideal stages N is given by following equation. This is true when the stripping factor 'S' is |
| A. | S > 1 |
| B. | S < 1 |
| C. | S = 1 |
| D. | S = ∞ |
| Answer» B. S < 1 | |
| 127. |
If f is defined as above, then which of the following applies to a feed at dew point? |
| A. | F = 1 |
| B. | F < 1 |
| C. | F > 1 |
| D. | 0 < f < 1 |
| Answer» B. F < 1 | |
| 128. |
Which of the following processes is not an example of adsorption applied to gaseous separations? |
| A. | Recovery of valuable solvent vapors from dilute mixture with air and other gases |
| B. | Dehumidification of air and gas |
| C. | Removal of objectionable odour and impurities from industrial gases |
| D. | Decolouration of yellow glycerene |
| Answer» E. | |
| 129. |
Which of the following solutions will follow Raoult's law most closely? |
| A. | A solution of benzene, toluene and oxylene |
| B. | 35% solution of camphor in water |
| C. | 35% solution of NH₃ in water |
| D. | A solution of polar organic compounds (not of homologs of a series) |
| Answer» B. 35% solution of camphor in water | |
| 130. |
Which of the following is a suitable absorbent for removal of H₂S from natural gas? |
| A. | Vetrocoke solution |
| B. | Monoethanol amine (MEA) |
| C. | Dilute |
| D. | Hot water |
| Answer» C. Dilute | |
| 131. |
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 | |
| 132. |
At what percentage (by volume) of alcohol composition, it forms an azeotrope with water? |
| A. | 90 |
| B. | 91.5 |
| C. | 95 |
| D. | 99 |
| Answer» D. 99 | |
| 133. |
Which of the following is not a continuous leaching equipment? |
| A. | Pachuka tank |
| B. | Kennedy extractor |
| C. | Bollman extractor |
| D. | Hydrocyclones |
| Answer» B. Kennedy extractor | |
| 134. |
Which of the following is used for the concentration of rubber latex? |
| A. | Agitated film evaporator |
| B. | Long tube vertical evaporator |
| C. | Short tube evaporator |
| D. | Calendria |
| Answer» B. Long tube vertical evaporator | |
| 135. |
The value of NA/(NA + NB), for steady state equimolal counter diffusion of two gases 'A' and 'B' is |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» C. 0.5 | |
| 136. |
If f = moles of vapour present per mole of feed, then the slope of feed line is (Mcabe-Thiele method) |
| A. | (1 - f)/f |
| B. | - (f - 1)/f |
| C. | - 1/f |
| D. | - f/(1 - f) |
| Answer» D. - f/(1 - f) | |
| 137. |
Which of the following is the most commonly used leaching solvent in vegetable oil industry? |
| A. | Phenol |
| B. | Hexane |
| C. | Furfurol |
| D. | Liquid SO₂ |
| Answer» C. Furfurol | |
| 138. |
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. | |
| 139. |
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 | |
| 140. |
Which of the following is not a continuous drier? |
| A. | Drum drier |
| B. | Spray drier |
| C. | Tunnel drier |
| D. | Tray drier |
| Answer» E. | |
| 141. |
Which of the following plays an important role in problems of simultaneous heat and mass transfer? |
| A. | Lewis number |
| B. | Schmidt number |
| C. | Prandtl number |
| D. | Sherwood number |
| Answer» B. Schmidt number | |
| 142. |
H₂S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H₂S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in metres) corresponding to an operating line given by, y = 5x + 0.001 is |
| A. | 2.0 |
| B. | 1.56 |
| C. | 1.0 |
| D. | 0.56 |
| Answer» B. 1.56 | |
| 143. |
A binary mixture of benzene and cyclohexane is separated by |
| A. | Flash vaporisation |
| B. | Extractive distillation |
| C. | Solvent extraction |
| D. | Ordinary distillation |
| Answer» C. Solvent extraction | |
| 144. |
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 | |
| 145. |
Can the efficiency of a plate in the distillation tower be greater than 100%? |
| A. | Yes |
| B. | Normally not; but is possible if infinite number of plates are put |
| C. | Never |
| D. | Yes ; if the reflux ratio is maximum |
| Answer» D. Yes ; if the reflux ratio is maximum | |
| 146. |
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 | |
| 147. |
The McCabe Δ L law states that the |
| A. | Molar heats of vaporisation of components are nearly equal |
| B. | Linear crystal growth rate depends on the degree of supersaturation |
| C. | Linear crystal growth rate does not depend on the crystal size |
| D. | Linear crystal growth rate depends on the crystal size |
| Answer» D. Linear crystal growth rate depends on the crystal size | |
| 148. |
Which of the following is an undesirable characteristic for the solvent used in gas absorption? |
| A. | Low vapor pressure |
| B. | Low viscosity |
| C. | High gas solubility |
| D. | None of these |
| Answer» E. | |
| 149. |
Which of the following equipments is not used in liquid-liquid extraction? |
| A. | Pachuka tank |
| B. | Agitated vessels |
| C. | Centrifugal extractors |
| D. | Packed towers |
| Answer» B. Agitated vessels | |
| 150. |
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 | |