. In a distillation column, with increase in the reflux ratio, the heat
removed in the cooler
(A) Increases
(B) Decreases
(C) Remains unaffected
(D) And the heat required in reboiler decreases
Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature
Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
Description : For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams (A) Increases (B) Decreases (C) Remain unaffected (D) Passes through a maximum
Last Answer : (A) Increases
Description : 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 ... (D) More number of trays are required and the residue composition is more dilute in methano
Last Answer : (A) Less number of trays are required
Description : Minimum reflux ratio in a distillation column results in (A) Optimum number of trays (B) Minimum reboiler size (C) Maximum condenser size (D) Minimum number of trays
Last Answer : (C) Maximum condenser size
Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower
Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux
Description : In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of (A) Area between operating line and 45° diagonal x-y diagram (B) Condenser and reboiler surfaces (C) Tower cross-section (D) None of these
Last Answer : (A) Area between operating line and 45° diagonal x-y diagram
Description : Pick out the wrong statement: (A) Reboiler is not used in open steam distillation (B) The separation of solutes of different molecular sizes in a liquid solution by use of a ... is used for calculating theoretical number of plates in a distillation column at normal operating reflux condition
Last Answer : (D) Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux condition
Description : A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are ... and without total reflux (D) The top and bottom compositions correspond to the maximum enrichment available
Last Answer : (D) The top and bottom compositions correspond to the maximum enrichment available
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 : For the same process conditions, the reflux ratio of an unlagged distillation column (A) Decreases in winter (B) Increases in winter (C) Increases in summer (D) None of these
Last Answer : (B) Increases in winter
Description : Total reflux in a distillation operation requires minimum (A) Reboiler load (B) Number of plates (C) Condenser load (D) All (A), (B) and (C)
Last Answer : (B) Number of plates
Description : In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads? Reflux conditions: (i) Reflux stream is completely liquid ... D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)
Last Answer : (D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)
Description : Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of ... in distillation column (D) The capacity of a distillation column is maximum at total reflux
Last Answer : (D) The capacity of a distillation column is maximum at total reflux
Description : The minimum number of theoretical plates is required for achieving a given separation in distillation column with (A) No reflux (B) Total reflux (C) Zero reflux ratio (D) Minimum reflux ratio
Last Answer : (B) Total reflux
Description : For a distillation column operating at minimum reflux, the (A) Concentration of liquid and vapour leaving a plate will be same (B) Reflux ratio will be maximum (C) Number of plates required will be maximum
Last Answer : (C) Number of plates required will be maximum
Description : In batch distillation with constant reflux, overhead product composition __________ with time. (A) Increases (B) Decreases (C) Does not vary (D) May increase on decrease, depends on the system
Last Answer : (B) Decreases
Description : With lapse of time, the overhead composition of light component in case of batch distillation with constant reflux (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease; depends on system
Description : When a multistage tray tower uses a minimum reflux ratio, it implies (A) Infinite trays and maximum reboiler heat load (B) Infinite trays and minimum reboiler heat load (C) Minimum trays and minimum reboiler heat load (D) Minimum trays and maximum reboiler heat load
Last Answer : (A) Infinite trays and maximum reboiler heat load
Description : With increase in gas rate, the number of transfer units, NtoG, for a fixed degree of absorption by a fixed amount of solvent (A) Increases (B) Decreases (C) Decreases linearly (D) Remains unaffected
Description : How the interest-level of a country is affected by FDI? (1) increases (2) decreases (3) remains unaffected (4) there is increase or decrease
Last Answer : (2) decreases Explanation: A higher international interest rate will decrease FDI since it means a higher cost of fund in international market, and vice versa. Interest rate is a measure of the cost of capital ... to a decrease in FDI. Interest rate and FDI can both be the cause and effect of other.
Description : How the interest-level of a country is affected by FDI ? (1) increases (2) decreases (3) remains unaffected (4) there is increase or decrease
Last Answer : decreases
Description : As the reflux ratio decreases, the (A) Separation becomes more efficient (B) Number of plates increases (C) Column diameter increases (D) None of these
Last Answer : (B) Number of plates increases
Description : The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will (A) Increase (B) Decrease (C) Remain same (D) Depend on saturated boiling point; may increase or decrease
Last Answer : (A) Increase
Description : With increase in the distance between the heat source and the object receiving the heat, the radiation heat transfer (A) Decreases (B) Increases (C) Increases exponentially (D) Remain unaffected
Last Answer : (A) Decreases
Description : Fenske equation determines the (A) Maximum number of ideal plates (B) Height of the distillation column (C) Minimum number of theoretical plates (D) Optimum reflux ratio
Last Answer : (C) Minimum number of theoretical plates
Description : At what value of reflux ratio, number of theoretical plates in a distillation column is minimum? (A) 0 (B) 1 (C) ∞ (D) < 1
Last Answer : (C) ∞
Description : 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
Last Answer : (A) 2
Description : The operating cost of a distillation column at minimum reflux ratio is (A) Minimum (B) Maximum (C) Infinite (D) Zero
Last Answer : (A) Minimum
Description : Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V' ratio (B) The extraction per unit ... and its crosssection is wider at the bottom (D) Vander wall adsorption is also called chemisorption
Last Answer : (D) Vander wall adsorption is also called chemisorption
Description : With the rise of temperature, the sensitivity of a bubble tube (A) Decreases (B) Increases (C) Remains unaffected (D) None of the above
Description : The efficiency of Diesei cycle with decrease in cut off (a) increases (b) decreases (c) remains unaffected (d) first increases and then decreases (e) first decreases and then increases.
Last Answer : Answer : a
Description : With increase in the liquid flow rate at a fixed gas velocity in a randomly packed counter current gas-liquid absorption column, the gas pressure drop (A) Decreases (B) Remains unchanged (C) Increases (D) Decreases exponentially
Last Answer : (C) Increases
Description : If cream is removed from milk, its density – (1) Increases (2) Decreases (3) Remains the same (4) May increase or decrease
Last Answer : (1) Increases Explanation: The density of pure fresh milk being on the average 1.032, while the density of fat globules is about 0.86. It follows that the removal of cream will increase the density, while the addition of water will decrease it.
Description : If cream is removed from milk, its density (1) Increases (2) Decreases (3) Remains the same (4) May increase or decrease
Last Answer : Increases
Description : If the amount of the steam used in steam distillation is increased, the temperature of distillation (A) Increases (B) Decreases (C) Remains unchanged (D) Depends on relative volatility
Description : Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact
Last Answer : (B) Decreases tray efficiency
Description : With increase in solvent rate, the number of transfer units, NtoG, for a fixed degree of absorption from a fixed amount of gas (A) Increases (B) Decreases (C) Decreases linearly (D) Remain unaffected
Description : With increase in temperature, the rate of extraction in leaching (solidliquid extraction system). (A) Increases (B) Decreases (C) Remain unaffected (D) Increases Linearly
Description : With an increase in pressure in gaseous phase chemical reactions, the fractional conversion __________ when the number of moles decreases. (A) Increases (B) Decreases (C) Remain unaffected (D) Unpredictable from the data
Description : With increase in temperature, the equilibrium conversion of a reversibleexothermic reaction (A) Decreases (B) Increases (C) Remain unaffected (D) Decreases linearly with temperature
Description : The equilibrium constant of chemical reaction __________ in the presence of catalyst. (A) Increases (B) Decreases (C) Remain unaffected (D) Can either increase or decrease (depends on the type of catalyst)
Last Answer : (C) Remain unaffected
Description : Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for (A) Constant molal overflow (B) Total reflux (C) Constant relative volatility (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
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 : The relative heat absorption for successively added equal areas of boiler convection heating surfaces__________ (A) Increases (B) Decreases (C) Remain unaffected (D) First increases and then decreases
Description : With increase in the concentration of the adsorbate, the integral heat of adsorption (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on the type of adsorbate
Description : With increase in temperature, the atomic heat capacities of all solid elements (A) Increases (B) Decreases (C) Remains unchanged (D) Decreases linearly
Description : With increase in the ratio of orifice diameter to pipe diameter, the fraction of the orifice pressure differential that is permanently lost (A) Increases (B) Decreases (C) Remains unchanged (D) Increases exponentially
Description : Increase amount of non-grain material on the straw walker _______ the walker losses a) Decreases b) Increases c) Unaffected d) Equal
Last Answer : b) Increase
Description : Reboiler is considered as one theoretical plate, because (A) Of the assumption that vapour and liquid leaving the reboiler are in equilibrium (B) Vapour is recycled to the column (C) Reboiler itself contains one plate (D) None of these
Last Answer : (A) Of the assumption that vapour and liquid leaving the reboiler are in equilibrium
Description : 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
Last Answer : (C) Never