০০। 'Absorption with chemical reaction' is involved in the removal of
ক) carbon dioxide from gaseous stream using alkaline solution.
খ) benzol from coke oven gas using solar oil/wash oil.
গ) ammonia from coke oven gas using refrigerated water.
ঘ) tar from coke oven gas in primary gas coolers using chilled water.
০১। 'ADDUCTS' and 'CLATHRATES' are used in case of
ক) extractive distillation.
খ) crystallisation.
গ) absorption.
ঘ) none of these.
০২। (NRe . NSc) is termed in mass transfer operation as the __________ number.
ক) Stanton
খ) Sherwood
গ) Peclet
ঘ) none of these
০৩। (NSh/NRe.NSc) is termed in mass transfer operation as the
ক) Stanton number
খ) Peclet number
গ) thermal diffusivity
ঘ) momentum diffusivity
০৪। 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
ক) 0.4
খ) 0.25
গ) 0.2
ঘ) 0.175
০৫। A binary mixture of benzene and cyclohexane is separated by
ক) flash vaporisation
খ) extractive distillation
গ) solvent extraction
ঘ) ordinary distillation
০৬। A 25 cm x 25 cm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m x 1m x 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is
ক) 1000
খ) 1500
গ) 2000
ঘ) 2500
০৭। A coalescer in a mixer-settler liquid-liquid extraction coloumn
ক) comprises of thin bed of substances of extended surface having high porosity.
খ) helps in increasing the bubble size entering the settler.
গ) helps in increasing the settling rate of the bubbles.
ঘ) all 'a', 'b', & 'c'.
০৮। 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
ক) 0.5
খ) 0.6
গ) 1.0
ঘ) 2.0
০৯। 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 At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,
ক) composition of vapors and that of liquid do not vary throughout the column.
খ) reboiler load and condenser load are minimum.
গ) the top and bottom compositions are unchanged with and without total reflux.
ঘ) the top and bottom compositions correspond to the maximum enrichment available.
১০। A good solvent used for absorption should not have very high
ক) viscosity
খ) vapor pressure
গ) freezing point
ঘ) all (a), (b) & (c)
১১। A liquid mixture contains 30% o-xylene, 60% p-xylene and 10%. m-xylene (all percentages in w/w). Which of the following statements would be true in respect of this mixture?
ক) The mixture exhibits an azeotrope at 101.3 kPa.
খ) The composition of the mixture, in percent by volume is: o-xylene 30, p-xylene 60. and m-xylene 10.
গ) The composition of the mixture in mole percent is: o-xylene 30, p-xylene 60 and m-xyoene 10.
ঘ) The mixture contain optical isomers.
১২। A minimum boiling azeotrope is exemplified by
ক) toluene-benzene
খ) acetone-carbon disulphide
গ) water-isobutyl alcohol
ঘ) none of these
১৩। A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.
ক) 21.7
খ) 20
গ) 27.3
ঘ) 18.7
১৪। A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height.
ক) 10-15
খ) 30-40
গ) 70-80
ঘ) 90-100
১৫। A packed tower compared to a plate tower for a particular mass transfer operation
ক) incurs smaller pressure drop.
খ) allows installation of cooling coils.
গ) is less costly when built in large sizes/diameters.
ঘ) is more suitable, if suspended solids are present in fluid streams.
১৬। 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 twopairs of partially miscible liquids ?
ক) 0
খ) 1
গ) 2
ঘ) 3
১৭। 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
ক) 0.54
খ) 1.04
গ) 1.24
ঘ) 1.94
১৮। A slurry is to be dried to produce flaky solid. Which dryer would you recommend ?
ক) Spray dryer
খ) Drum dryer
গ) Rotary dryer
ঘ) Dielectric dryer
১৯। A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))
