McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 151. |
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» A. Pure component | |
| 152. |
__________ extractor is used for the concentration of radioactive nuclear waste. |
| A. | Pulsed column |
| B. | Sieve plate |
| C. | Mixer-settler |
| D. | Bollman |
| Answer» A. Pulsed column | |
| 153. |
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» B. Water from petrol | |
| 154. |
Use of packed towers for distillation is generally limited to the |
| A. | Small sizes |
| B. | Multi-component distillation |
| C. | High pressure operation |
| D. | Vacuum distillation |
| Answer» A. Small sizes | |
| 155. |
Dimension of mass diffusivity is the same as that of |
| A. | Kinematic viscosity |
| B. | Dynamic viscosity |
| C. | Surface tension |
| D. | Pressure |
| Answer» A. Kinematic viscosity | |
| 156. |
Paper industry employs __________ driers. |
| A. | Cylinder |
| B. | Rotary |
| C. | Spray |
| D. | Fluidised bed |
| Answer» A. Cylinder | |
| 157. |
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 cannot be increased by either reducing the mixture temperature or by increasing the total pressure |
| Answer» D. Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure | |
| 158. |
Laboratory determination of the diffusivity of vapor is done by __________ method. |
| A. | Wetted wall column |
| B. | Gilliland's |
| C. | Winkelmann's |
| D. | Wike's |
| Answer» C. Winkelmann's | |
| 159. |
The relation among various mass transfer co-efficients (M.T.C) for ideal gases is given by (where, Kc & Km are M.T.C. for equimolar counter diffusion with concentration & mole fraction respectively as the driving force. and, Kp= M.T.C. for diffusion of a gas through a stagnant inert gas with pressure as driving force.) |
| A. | Kc = Kp = Km |
| B. | Kc = Kp/RT = Km . RT/P |
| C. | Kc = Kp . RT = Km . RT/p |
| D. | None of these |
| Answer» C. Kc = Kp . RT = Km . RT/p | |
| 160. |
Pick out the wrong statement: |
| A. | Change in barometric pressure does not affect the relative humidity |
| B. | In case of a packed tower, the operating velocity is about half of the flooding velocity, generally |
| C. | 'Elution' means the desorption of the adsorbed solute by a solvent |
| D. | The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity |
| Answer» D. The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity | |
| 161. |
The temperature of water cooled in cooling tower is always __________ temperature of entering air. |
| A. | More than the wet bulb |
| B. | Less than the wet bulb |
| C. | Equal to the wet bulb |
| D. | Equal to the dry bulb |
| Answer» A. More than the wet bulb | |
| 162. |
Reverse osmosis is also called |
| A. | Dialysis |
| B. | Electrodialysis |
| C. | Diffusion |
| D. | Ultra-filtration |
| Answer» D. Ultra-filtration | |
| 163. |
Design calculation for multiple component distillation is done by |
| A. | Ponchon-Savarit method |
| B. | McCabe-Thiele method |
| C. | Enthalpy concentration method |
| D. | Tray to tray calculations |
| Answer» D. Tray to tray calculations | |
| 164. |
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» D. All (A), (B) and (C) | |
| 165. |
The unit of volumetric diffusivity is |
| A. | cm2/sec |
| B. | cm/sec |
| C. | cm3/sec |
| D. | cm2/sec2 |
| Answer» A. cm2/sec | |
| 166. |
Drying of a wet solid under constant drying conditions means the exposure of the wet solid to the air of constant |
| A. | Humidity |
| B. | Velocity |
| C. | Temperature |
| D. | All (A), (B) & (C) |
| Answer» D. All (A), (B) & (C) | |
| 167. |
The diffusivity (D) in a binary gas mixture is related to the pressure (P) as |
| A. | D ∝ P 0.5 |
| B. | D ∝ 1/P 0.5 |
| C. | D ∝ 1/P |
| D. | D ∝ 1/P 1.5 |
| Answer» C. D ∝ 1/P | |
| 168. |
In liquid extraction, if the selectivity is unity, then |
| A. | Separation of the constituents is the most effective |
| B. | No separation will occur |
| C. | Amount of solvent required will be minimum |
| D. | Solvent flow rate should be very low |
| Answer» B. No separation will occur | |
| 169. |
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» C. Never | |
| 170. |
H2S present in naphtha reformed gas is removed by absorbing with |
| A. | Ethanolamine |
| B. | K2CO3 |
| C. | HCl |
| D. | Vacuum gas oil |
| Answer» A. Ethanolamine | |
| 171. |
Dorr thickener is an equipment used for |
| A. | Classification |
| B. | Sedimentation |
| C. | Clarification |
| D. | Leaching |
| Answer» B. Sedimentation | |
| 172. |
With the lowering of equilibrium pressure, at a given temperature, the amount of adsorbate on the adsorbent |
| A. | Increases |
| B. | Decreases |
| C. | Remain same |
| D. | Either (A) or (B), depends on the system |
| Answer» B. Decreases | |
| 173. |
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» A. Film | |
| 174. |
A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is: |
| A. | 0.54 |
| B. | 1.04 |
| C. | 1.24 |
| D. | 1.94 |
| Answer» C. 1.24 | |
| 175. |
__________ extractor uses centrifugal force for separating the two phases. |
| A. | Treybal |
| B. | Scheibel |
| C. | Podbielniak |
| D. | None of these |
| Answer» C. Podbielniak | |
| 176. |
With increase in temperature, the mutual solubility of two liquids |
| A. | Increases |
| B. | Decreases |
| C. | Remains unchanged |
| D. | Decreases exponentially |
| Answer» A. Increases | |
| 177. |
The operating cost of a distillation column at minimum reflux ratio is |
| A. | Minimum |
| B. | Maximum |
| C. | Infinite |
| D. | Zero |
| Answer» A. Minimum | |
| 178. |
For a single component absorber, the operating line is straight only when plotted in term of __________ units. |
| A. | Partial pressure |
| B. | Mole ratio |
| C. | Mole fraction |
| D. | None of these |
| Answer» B. Mole ratio | |
| 179. |
The cooling effect in a cooling tower cannot 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» D. None of these | |
| 180. |
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» B. Isotopes of uranium | |
| 181. |
Sodium bicarbonate is produced during soda ash manufacture using a __________ tower. |
| A. | Plate |
| B. | Baffle |
| C. | Packed |
| D. | None of these |
| Answer» B. Baffle | |
| 182. |
Leaching rate is independent of the |
| A. | Agitation |
| B. | Temperature |
| C. | Particle size |
| D. | None of these |
| Answer» D. None of these | |
| 183. |
With increase in temperature, the rate of leaching increases, because the |
| A. | Diffusivity of solute increases |
| B. | Viscosity of solvent decreases |
| C. | Thermal conductivity of solute increases |
| D. | None of these |
| Answer» A. Diffusivity of solute increases | |
| 184. |
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 (A) or (B); depends on the solid |
| Answer» A. Less than | |
| 185. |
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» A. 2 | |
| 186. |
Which of the following is not a batch drier? |
| A. | Truck drier |
| B. | Agitated pan drier |
| C. | Fluidised bed drier |
| D. | Vacuum shelf drier |
| Answer» C. Fluidised bed drier | |
| 187. |
Acetic acid will be most economically separated from a dilute solution of acetic acid in water by |
| A. | Solvent extraction |
| B. | Continuous distillation |
| C. | Evaporation |
| D. | Absorption |
| Answer» A. Solvent extraction | |
| 188. |
The main reason for dividing a tall packed tower into series of small towers is to |
| A. | Minimise the overall pressure drop |
| B. | Avoid flooding |
| C. | Reduce liquid hold up |
| D. | Avoid channelling |
| Answer» D. Avoid channelling | |
| 189. |
The most efficient cooling tower out of the following is |
| A. | Induced draft |
| B. | Forced draft |
| C. | Natural draft |
| D. | Atmospheric |
| Answer» A. Induced draft | |
| 190. |
Molecular distillation is |
| A. | High temperature distillation |
| B. | For heat-sensitive materials |
| C. | Very low pressure distillation |
| D. | Both (B) and (C) |
| Answer» D. Both (B) and (C) | |
| 191. |
The value of NA/(NA + NB) for steady state molecular diffusion of gas 'A' through nondiffusing gas 'B' is |
| A. | 1 |
| B. | ∞ |
| C. | 0.5 |
| D. | 2 |
| Answer» A. 1 | |
| 192. |
All moisture in a non-hygroscopic material is the __________ moisture. |
| A. | Free |
| B. | Equilibrium |
| C. | Unbound |
| D. | Bound |
| Answer» C. Unbound | |
| 193. |
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» A. Increases with temperature | |
| 194. |
Raschig ring made of porcelain cannot be used for treating concentrated |
| A. | Hydrochloric acid |
| B. | Nitric acid |
| C. | Alkalis |
| D. | Sulphuric acid |
| Answer» C. Alkalis | |
| 195. |
Use of natural draft cooling tower is practised, when the air has low |
| A. | Humidity |
| B. | Temperature |
| C. | Both 'a' & 'b' |
| D. | Neither 'a' nor 'b' |
| Answer» C. Both 'a' & 'b' | |
| 196. |
At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent. |
| A. | 100 |
| B. | zero |
| C. | 50 |
| D. | Between 0 and 100 |
| Answer» B. zero | |
| 197. |
Tower diameter may be decreased by |
| A. | Using higher reflux ratio |
| B. | Use of increased tray spacing |
| C. | Increasing the liquid flow rate |
| D. | Increasing the vapour flow rate |
| Answer» B. Use of increased tray spacing | |
| 198. |
Pick out the wrong statement. |
| A. | The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are the same for NSc = NPr= 1 |
| B. | 1 Nm3 of dry air is lighter than 1Nm3 of humid air |
| C. | The Lewis number of a mixture is unity, when the thermal diffusivity is equal to the mass diffusivity |
| D. | An Azeotropic mixture of two liquids has boiling point higher than either of them, when it shows negative deviation from Raoult's Law |
| Answer» B. 1 Nm3 of dry air is lighter than 1Nm3 of humid air | |
| 199. |
The humid volume may be increased by increasing the |
| A. | Temperature at constant humidity |
| B. | Humidity at constant temperature |
| C. | Both (A) and (B) |
| D. | Neither (A) nor (B) |
| Answer» C. Both (A) and (B) | |
| 200. |
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» A. (1 + Ro) = Ro/Ri | |
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