chemical engineering Mcqs
2401. The specific surface of spherical particles is given by (where D and ? are diameter and density of particle) ?
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A. 2/D.?

B. 4/D.?

C. 12/D.?

D. 6/D.?
2402. _____________ is the most suitable for compounding rubber and plastic solids ?
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A. Charge can mixer

B. Pug mill

C. Banbury mixer

D. Pan mixer

2403. The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an______________?
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A. Bag filter

B. Wet scrubber

C. Cyclone separator

D. Electrostatic precipitator
2404. Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids (> 50000 centipoise) ?
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A. Flat blade turbine

B. Propeller

C. Helical screw

D. Curved blade turbine

2405. The optimum moisture content in solids to be crushed/ground ranges from _______________ percent?
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A. 3 to 4

B. 15 to 20

C. 10 to 15

D. 8 to 10

2406. For which of the following unit operations, Lewis number is of significance ?
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A. Humidification

B. Gas absorption

C. Binary distillation

D. Adsorption

2407. Bucket elevators are not suitable for the vertical lifting of __________ materials?
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A. Small lumpy (e.g. grains and sand)

B. Fine (e.g. 200 mesh size coal)

C. Sticky (e.g. clay paste)

D. Free flowing

2408. In a grinding operation, the limiting particle size is the size of the _______________ particle in the sample?
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A. Neither A. nor B.

B. Largest

C. Either A. or B.

D. Smallest

2409. For transporting pasty material, one will use a/an__________________?
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A. Screw conveyor

B. Bucket elevator

C. Belt conveyor

D. Apron conveyor

2410. If a two phase system is in physical equilibrium; then it means that, the_____________________?
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A. al to that from vapor phase to liquid phase

B. Temperature of the liquid phase is equal to that of the vapor phase

C. Total pressure throughout the liquid phase is equal to that throughout the vapor phase

D. Escaping tendency of each component from the liquid phase to the vapor phase is exactly

E. All A., B. and C.
2411. Which of the following gives the crushing energy required to create new surface ?
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A. Ficks law

B. None of these

C. Taggarts rule

D. Rittingers Law
2412. Pick out the material having minimum Rittingers number?
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A. Galena

B. Pyrite

C. Quartz

D. Calcite

2413. Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle)?
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A. V/D.S

B. V/6D.S

C. 6.V/D.S

D. D.S/V

2414. Capacity of a rotary dryer depends on its __________________?
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A. rpm

B. Inclination with ground surface

C. Both A. and B.

D. Neither A. nor B.

2415. The crushed material received for separation is called feed or_________________?
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A. Middling

B. Heading

C. Tailing

D. Concentrate

2416. For a binary mixture with low relative volatility, continuous rectification to get pure products will require_____________________?
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A. Low reflux ratio

B. High reflux ratio

C. Small cross-section column

D. Less number of trays

2417. With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature) ?
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A. Increases

B. Remains unchanged

C. Decreases linearly

D. Decreases

2418. Chance process is used for the________________?
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A. Cleaning of coal

B. Water treatment

C. Concentration of iron ore

D. Concentration of pyrites

2419. Cement clinker is reduced to fine size by a _____________________?
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A. Hammer mill

B. Roll crusher

C. Ball mill

D. Tube mill
2420. A _______________ employs a set of screen across a flow channel for the separation of dirt/rust from a flowing liquid stream?
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A. Strainer

B. Thickener

C. Clarifier

D. Classifier

2421. Which one is a filter aid ?
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A. None of these

B. Calcined lime

C. Diatomaceous earth

D. Canvas fabric

2422. Flow of filtrate through the cake in a plate and frame filter press is best described by the ______________ equation?
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A. Fannings

B. Hagen-Poiseuilles

C. Kremser

D. Kozeny-Carman
2423. Carbon black is pulverised in a_______________?
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A. Hammer crusher

B. Gyratory crusher

C. Ball mill

D. Roll crusher

2424. Berl saddle made of carbon cannot be used for ___________________?
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A. Oxidising atmosphere

B. Alkalis

C. SO2

D. H2SO4

2425. Use of grinding aids results in the ___________________?
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A. Enhanced production rate

B. Finer products

C. Both A. & B.

D. Neither A. nor B.
2426. Mixing mechanism employed in a pan mixer is by ________________?
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A. None of these

B. Mulling

C. Kneading

D. Dispersion

2427. As the reflux ratio decreases, the_________________?
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A. None of these

B. Column diameter increases

C. Number of plates increases

D. Separation becomes more efficient

2428. Where the density difference of the two liquid phase to be separated is very small (as in milk cream separator), the most suitable separator is a____________________?
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A. Sparkler filter

B. Disc bowl centrifuge

C. Batch basket centrifuge

D. Sharpies super-centrifuge

2429. Water-ethyl alcohol solution can be concentrated (in respect of alcohol concentration) by ________________ distillation?
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A. Atmospheric

B. High pressure

C. Vacuum

D. None of these

2430. Which is the most suitable conveyor for transportation of sticky material ?
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A. Apron conveyor

B. Belt conveyor

C. Screw conveyor

D. Pneumatic conveyor

2431. In an absorber, HETP does not vary with the____________________?
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A. None of these

B. Flow rate of liquid

C. Type and size of packing

D. Flow rate of gas

2432. To get a fine talc powder from its granules, the equipment used is____________________?
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A. Gyratory crusher

B. Jaw crusher

C. Roller crusher

D. Ball mill
2433. Molten ammonium nitrate is mixed with ground limestone in fertilizer plant in a__________________?
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A. Muller mixer

B. Banbury mixer

C. Mixer-extruder

D. Pug mill
2434. Filtration capacity of a rotary drum vacuum filter depends upon the_______________?
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A. Cake thickness

B. Characteristics of the feed slurry

C. Both A. & B.

D. Neither A. nor B.

2435. The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is_________________?
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A. Induced draft cooling tower

B. Spray chamber

C. None of these

D. Natural draft cooling tower

2436. Ribbon blenders are exclusively meant for __________________?
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A. Bath mixing

B. Blending miscible liquids

C. Non-flowing powder and thin pastes

D. Continuous mixing

2437. Removal of activated carbon from glycerine is done by _________________?
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A. Batch basket centrifuge

B. Rotary vacuum filter

C. None of these

D. Plate and frame filter
2438. The capacity of a gyratory crusher is ______________ that of a jaw crusher with the same gape, handling the same feed & for the same product size range.?
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A. 2.5 times

B. 5 times

C. 10 times

D. Same as

2439. Which of the following remains constant during evaporative cooling process with recirculated water supply ?
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A. None of these

B. Relative humidity

C. Wet bulb temperature

D. Partial pressure of vapour

2440. Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are________________?
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A. Bi-carbonates

B. Carbonates

C. Sulphates

D. Silicates & phosphates
2441. increasing the capacity of a screen _______________ the screen effectiveness?
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A. Does not effect

B. None of these

C. Increases

D. Decreases
2442. Size reduction of moulding powders, waxes, resins & gums are done in a _______________ mill?
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A. Cage

B. Hammer

C. Both A. & B.

D. Neither A. nor B.

2443. The sphericity of a solid particle of cubical shape is ___________________?
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A. (?/6)1/2

B. ?

C. ?/3

D. (?/6)1/3
2444. Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm) ?
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A. 0.087 L.S

B. L.S/0.087

C. 0.01 L.S

D. L.S

2445. Trommels are revolving screens which normally operate in the range of _______________ rpm?
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A. 40 50

B. 1 2

C. 15 20

D. 60 75

2446. Filtration of water in a paper mill is done by a/an _______________ filter?
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A. Sparkler

B. Vacuum leaf

C. Plate and frame

D. Open sand
2447. Dispersion of a gas through liquid is done by using a__________________?
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A. Kneader

B. None of these

C. Masticator

D. Sparger
2448. Filtration operation carried out by continuous increase of the inlet pressure of slurry, is called the _____________ filtration?
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A. Varying rate

B. Constant rate

C. Constant pressure

D. Varying pressure

2449. Drying operation under vacuum is carried out to __________________?
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A. Dry those materials which have very high unbound moisture content

B. Dry materials having high bound moisture content

C. Increase drying temperature

D. Reduce drying temperature
2450. Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the ______________________?
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A. Ultimate strength of the material

B. State or manner of application of the crushing force

C. Elastic constant of the material

D. All A., B. and C.