In a binary distillation column, if the feed contains 40 mole % vapour,
the q line will have a slope of
(A) 1.5
(B) -0.6
(C) -1.5
(D) 0.6
Description : If f = moles of vapour present per mole of feed, then the slope of feed line is (McCabe-Thiele method) (A) (1 - f)/f (B) - (f - 1)/f (C) -1/f (D) -f/(1 - f)
Last Answer : (C) -1/f
Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity
Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer coefficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s
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 : When the feed to a distillation column is a saturated liquid, slope of thefeed line is (A) Zero (B) Unity (C) Infinity (D) None of these
Last Answer : (C) Infinity
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 : 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 : 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 gaseous reaction 2A → B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is (A) 1 (B) -0.5 (C) -0.25 (D) 0
Last Answer : (C) -0.25
Description : The gas phase reaction 2A ⇌ B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is (A) 2/3 (B) 5/8 (C) 1/3 (D) 3/8
Last Answer : (B) 5/8
Description : Inside the distillation column, the (A) Driving force for the vapour flow is the pressure drop (B) Liquids are not always at their bubble points (C) Pressure increases gradually from bottom to the top of the column (D) None of these
Last Answer : (A) Driving force for the vapour flow is the pressure drop
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 : 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 : 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 rectifying section of a continuous distillation column, the (A) Vapour is enriched with low boilers (B) Vapour is enriched with high boilers (C) Liquid is stripped of high boilers (D) None of these
Last Answer : (B) Vapour is enriched with high boilers
Description : 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 ... in the column. (A) 5 (B) 9 (C) 12 (D) 28
Last Answer : (C) 12
Description : 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
Last Answer : (C) Increased reflux ratio
Description : 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 fraction vaporised but not the product composition (D) Neither the product composition nor the fraction vaporised
Last Answer : (C) The fraction vaporised but not the product composition
Description : In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when (A) Saturated feed is not used (B) An azeotrope forms (C) The latent ... vaporisation of the more and less volatile components are greatly different (D) A total condenser is used
Last Answer : (D) A total condenser is used
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 : . For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient, can't be predicted
Last Answer : (A) Increase
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
Description : The slope of the operating line for a single component co-current absorber when plotted in terms of mole ratio units is (A) 0 (B) ∞ (C) -ve (D) +ve
Last Answer : (C) -ve
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 : For the equilibrium: `LiCl.3NH_(3(s))hArrLiCl.NH_(3(s))+2NH_(3)`, `K_(p)=9 atm^(2)` at `40^(@)C`. A `5 litre` vessel contains `0.1` mole of `LiCl.NH_(
Last Answer : For the equilibrium: `LiCl.3NH_(3(s))hArrLiCl.NH_(3(s))+2NH_(3)`, `K_(p)=9 atm^(2)` at `40^( ... backward reaction for completion? A. 5 B. 9 C. 3 D. 1
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 : 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)
Last Answer : (C) Both (A) & (B)
Description : The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n octane into pure compounds each at 1 atm is (A) -2 RT ln 0.5 (B) -RT ln 0.5 (C) 0.5 RT (D) 2 RT
Last Answer : (B) -RT ln 0.5
Description : At 60° C, vapour pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60° C exerts a pressure of 39.223 kPa; the liquid phase and vapour phase mole ... respectively. Activity co-efficient of methanol is (A) 1.572 (B) 1.9398 (C) 3.389
Last Answer : (A) 1.572
Description : The-relative volatility for separation of a non-ideal binary mixture by distillation should be (A) 0 (B) 1 (C) > 1 (D) < 1
Last Answer : (C) > 1
Description : For a binary mixture distillation process, the degree of freedom is 2. However, if the pressure is fixed in this process, the number of independent variables in this process will be (A) 1 (B) 0 (C) 2 (D) 3
Last Answer : (A) 1
Description : Gibbs-Duhem equation (A) States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure (B) Applies only to binary systems (C) Finds no application in gas-liquid equilibria involved in distillation (D) None of these
Last Answer : (A) States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Description : For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be (A) 6738.9 (B) 6753.5 (C) 7058.3 (D) 9000
Last Answer : (B) 6753.5
Description : If a1 and a2 are the relative volatilities when the pressure in the distillation column is 1 and 2 atm respectively. Pick out the correct statement. (A) a1 = a2 (B) a1 = 2a2 (C) a1 = 0.5 a2 (D) None of these
Last Answer : (D) None of these
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 slope of 9-line is determined by the (A) Reflux ratio (B) Plate efficiency to be achieved (C) Thermal condition of the feed (D) Relative volatility
Last Answer : (C) Thermal condition of the feed
Description : In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapour, because (A) Temperature is less (B) Total pressure is less (C) Mixing of steam ... not so intimate as to result in equilibrium condition (D) Saturated steam is used for steam distillation
Last Answer : (C) Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition
Description : Henry's law states that the (A) Partial pressure of a component over a solution is proportional to its mole fraction in the liquid (B) Partial pressure of a component over a solution ... pressure (D) Partial pressure is equal to the product of the mole fraction and total pressure
Last Answer : (A) Partial pressure of a component over a solution is proportional to its mole fraction in the liquid
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 : Contour bunging is adopted where land slope is — % a. 6 b. 12 c. 18 d. 21
Last Answer : a. 6
Description : Ferrous sulphate contains — % Fe a. 10 b. 20 c. 30 d. 40
Last Answer : b. 20
Description : For which of the following unit operations, Lewis number is ofsignificance? (A) Adsorption (B) Binary distillation (C) Gas absorption (D) Humidification
Last Answer : (D) Humidification
Description : Pick out the wrong statement. (A) The mole fraction of solute is directly proportional to the molality of a 'dilute' solution (B) For a non-reacting binary mixture of ideal gases, the partial ... at all temperature (D) The relative volatility of a binary mixture at the Azeotropic composition is 1
Last Answer : (C) Azeotropes obey Raoult's law at all temperature
Description : McCabe-Thiele method of binary distillation does not assume that the (A) Sensible heat changes are negligible compared with latent heat changes (B) Molar latent heats of all components are equal (C) Heat of mixing is negligible (D) None of these
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 : 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 : Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation. (A) Molecular (B) Extractive (C) Steam (D) Simple
Last Answer : (D) Simple
Description : Flash distillation is suitable for separating the constituents of a binary system, which (A) Form minimum boiling azeotrope (B) Have very wide boiling points (C) Have very close boiling points (D) Form constant boiling azeotrope
Last Answer : (B) Have very wide boiling points
Description : Pick out the wrong statement. (A) Constant pressure distillation cannot separate an Azeotropic mixture (B) Relative volatility of a binary mixture changes appreciably with the minor change in ... unity (D) Flash distillation is practised on wide spread scale in petroleum refinery
Last Answer : (B) Relative volatility of a binary mixture changes appreciably with the minor change in temperature
Description : Pick out the correct statement. (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of ... Flash distillation is suitable for separating components which have very close boiling temperature
Last Answer : (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of nonideal binary system by distillation
Description : A binary mixture of benzene and cyclohexane is separated by (A) Flash vaporisation (B) Extractive distillation (C) Solvent extraction (D) Ordinary distillation
Last Answer : (B) Extractive distillation