In case of absorption & stripping, the interface of the liquid & gas
phases are present in equilibrium, when the diffusional resistance of
__________ is zero.
(A) Interface
(B) Gas phase
(C) Liquid phase
(D) All 'a', 'b' & 'c'
Description : Pick out the wrong statement (A) Co-current absorbers are usually used, when the gas to be dissolved in the liquid is a pure substance (B) In case of gas absorption, HETP is ... reaction (D) In actual practice, absorption is an endothermic process, while stripping is an exothermic process
Last Answer : (D) In actual practice, absorption is an endothermic process, while stripping is an exothermic process
Description : When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is (A) Same in both the phases (B) Zero in both the phases (C) More in vapour phase (D) More in liquid phase
Last Answer : (A) Same in both the phases
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
Description : The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are: (A) 1 (B) 2 (C) 3 (D) 0
Last Answer : (B) 2
Description : In the absorption of ammonia in water, the main resistance to absorption is by the __________ phase. (A) Liquid (B) Gas (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (B) Gas
Description : Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer coefficient based on the liquid side for dilute systems for the above was estimated to be 4 ... -4 (C) 5.6 10 -3 (D) 8.5 10 -3
Last Answer : (B) 8.5 × 10 -4
Description : Pick out the wrong statement: (A) Absorption factor is constant, when the equilibrium and operating lines are straight (B) In case of a stripper, the equilibrium curve is always below ... (D) In the absorption of low solubility gases, the liquid film is the controlling resistance
Last Answer : (B) In case of a stripper, the equilibrium curve is always below the operating line
Description : During bottling of cold drinks (e.g. Pepsi), the main resistance to mass transfer for the absorption of carbon dioxide in water lies in the (A) Gas film (B) Liquid film (C) Liquid-gas interface
Last Answer : (B) Liquid film
Description : When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is (A) More in vapour phase (B) More in liquid phase (C) Same in both the phases (D) Replaced by chemical potential which is more in vapour phase
Last Answer : (C) Same in both the phases
Description : The individual mass transfer co-efficients (moles/m2s) 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 ... A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side
Last Answer : (B) Gas side
Description : For stripping of a gas in a counter current stripper, the operating line (A) Lies above the equilibrium curve (B) Lies below the equilibrium curve (C) Can lie above or below the equilibrium curve (D) Is always parallel to the equilibrium curve
Last Answer : (C) Can lie above or below the equilibrium curve
Description : Binary distillation involves the mass transfer by __________ at the gasliquid interface. (A) Unidirectional diffusion from liquid to gas phase (B) Unidirectional diffusion from gas to liquid phase (C) Either 'a' or 'b' (D) A counter diffusion at an almost equal molar rate
Last Answer : (D) A counter diffusion at an almost equal molar rate
Description : . The absorption factor is defined as (where, L = liquid flow rate, G = gas flow rate and, m = slope of the equilibrium line). (A) L/mG (B) G/mL (C) mL/G (D) LG/m
Last Answer : (A) L/mG
Description : In the desorption of highly soluble gas from the liquid, the main resistance will be in the __________ phase. (A) Gas (B) Liquid (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (B) Liquid
Description : The necessary condition for phase equilibrium in a multiphase system of N components is that the (A) Chemical potentials of a given component should be equal in all phases (B) Chemical potentials of all ... potentials of any given component in all the phases should be the same (D) None of these
Last Answer : (A) Chemical potentials of a given component should be equal in all phases
Description : The necessary and sufficient condition for equilibrium between two phases is (A) The concentration of each component should be same in the two phases (B) The temperature of each phase should be same ( ... the two phases (D) The chemical potential of each component should be same in the two phases
Last Answer : (D) The chemical potential of each component should be same in the two phases
Description : In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas ... (C) Less than 1 kg of C is transferred to B (D) No amount of C is transferred to B
Last Answer : (A) The entire amount of C is transferred to solvent B
Description : Solid and liquid phases of a substance are in equilibrium at the (A) Critical temperature (B) Melting point (C) Freezing point (D) Both (B) and (C)
Last Answer : D) Both (B) and (C)
Description : When acetone is added in a two layer mixture of methyl isobutyl ketone and water at 30°C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system ... at the concentration of the plait point (D) All (A), (B) and (C
Last Answer : (D) All (A), (B) and (C
Description : The reciprocal of stripping factor is termed as (A) Selectivity index (B) Relative volatility (C) Absorption factor (D) Murphree efficiency
Last Answer : (C) Absorption factor
Description : To get high tray efficiency (A) Interfacial surface between liquid and gas phase should be large (B) Time of contact between the two phases should be less (C) Gas velocity should be very low (D) Liquid entrainment should be severe
Last Answer : (A) Interfacial surface between liquid and gas phase should be large
Description : One of the methods of purification of leach liquor is ion exchange, which involves (A) Exchange between two liquid phases (B) Exchange between a gaseous phase and a liquid phase (C) Exchange between a liquid phase and an organic resin phase (D) Exchange between a solid phase and a gas phase
Last Answer : (C) Exchange between a liquid phase and an organic resin phase
Description : In gas-liquid contact operation, the number of ideal stages, N = (xa - xb )/(xb - x *b ). This is true when the stripping factor 'S' is (A) S > 1 (B) S < 1 (C) S = 1 (D) S = ∞
Last Answer : (A) S > 1
Description : The phenomenon occuring during pumping of a liquid solution containing dissolved gases, which may come out of the solution giving rise to gas pockets, is termed as (A) Evaporation (B) Cavitation (C) Sublimation (D) Stripping
Last Answer : (B) Cavitation
Description : In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for (A) Fast reactions in catalyst of small pore diameter (B) Fast reaction in catalyst ... reactions in catalyst of small pore diameter (D) Slow reactions in catalyst of large pore diameter
Last Answer : (C) Slow reactions in catalyst of small pore diameter
Description : Steady state equimolal counter diffusion occurs in case of (A) Leaching (B) Absorption (C) Binary phase distillation (D) Liquid-liquid extraction
Last Answer : (C) Binary phase distillation
Description : What is the state at which all three phases of water coexist in equilibrium? A. Tripoint of water B. Triple point of water C. Triple phase point of water D. Phase point of water
Last Answer : Triple point of water
Description : If a system involves two phases, it is in ______ equilibrium when the mass of each phase reaches an equilibrium level and stays there. A. Chemical B. Thermal C. Mechanical D. Phase
Last Answer : Phase
Description : Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation. (A) Gibbs-Duhem (B) Maxwell's (C) Clapeyron (D) None of these
Last Answer : (C) Clapeyron
Description : For multi-component multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases. (A) Chemical potential (B) Fugacity (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : (4) Water drops in a dispersion medium of air Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed ... or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.
Last Answer : Conduction band electrons have more mobility than holes because they – (1) are lighter (2) experience collision less frequently (3) have negative charge (4) need less energy to move them
Description : (2) Fat is dispersed in water Explanation: A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed ... Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.
Last Answer : The presence of ozone in the stratosphere is responsible for – (1) increasing the average global temperature in recent years (2) higher rate of photosynthesis (3) checking the penetration of ultra-violet rays to the earth (4) supplying oxygen for people travelling in jets
Description : The temperature at which both liquid and gas phases are identical, is called the __________ point. (A) Critical (B) Triple (C) Freezing (D) Boiling
Last Answer : (A) Critical
Description : The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point. (A) Freezing (B) Triple (C) Boiling (D) Boyle
Last Answer : B) Triple
Description : At __________ point, all the three phases (i.e. solid, liquid and gas) co exist. (A) Eutectic (B) Triple (C) Plait (D) Critical
Last Answer : (B) Triple
Description : At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm. ... (B) μ°+ R ln f (C) μ° + T ln f (D) μ° + R/T ln f
Last Answer : (A) μ° + RT ln f
Description : In case of absorption, both the operating and equilibrium lines will be straight for (A) Isothermal operation (B) Dilute solutions (C) Dilute solutions and isothermal operation (D) None of these
Last Answer : (C) Dilute solutions and isothermal operation
Description : As the reflux ratio in a distillation column is increased from the minimum, the (A) Slope of the operating line in stripping section decreases (B) Number of plates decreases very slowly first ... decreases and then increases (D) Liquid flow increases while the vapor flow decreases for a system
Last Answer : (C) Total cost first decreases and then increases
Description : In stripping section of continuous distillation column, the (A) Liquid is stripped of high boiler (B) Liquid is enriched with high boiler (C) Vapour is stripped of low boiler (D) None of these
Last Answer : (B) Liquid is enriched with high boiler
Description : In distillation where q is defined as the moles of liquid flow in the stripping section per mole of feed introduced, for saturated liquid feed (A) q > 1 (B) q < 1 (C) q = 1 (D) q = 0
Last Answer : (C) q = 1
Description : In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)
Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : What is an example of the liquid to gas phase change equilibrium?
Last Answer : Need answer
Description : In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants) (A) Addition of inert gas favours the forward reaction, when Δx is positive (B) Pressure has no effect on equilibrium, when Δn = ... any value of Δx (+ ve, - ve) or zero) (D) All 'a', 'b' & 'c'
Last Answer : D) All 'a', 'b' & 'c'
Description : With increase in temperature, the equilibrium __________ rises in case of endothermic reaction. (A) Constant (B) Conversion (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (B) Conversion
Description : In McCabe-Thiele method of theoretical plate calculation for a distillation column, the operating lines of stripping and rectifying sections coincide with the diagonal at __________ reflux. (A) Total (B) Minimum (C) Operating (D) Maximum permissible
Last Answer : (A) Total
Description : In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B
Last Answer : (C) Both (A) & (B)
Description : The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding
Last Answer : Answer: B
Description : In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is ... B) Chemical potentials (C) Activity co-efficients (D) Mass transfer co-efficients
Last Answer : (A) Concentrations