chemical engineering Mcqs
2701. Arrange the following size reduction equipment in the decreasing order of the average particle size produced by each of them ?
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A. Fluid energy mill, Jaw crusher, Ball mill

B. Jaw crusher, Ball mill, Fluid energy mill

C. Fluid energy mill, Ball mill, Jaw crusher

D. Ball mill, Jaw crusher, Fluid energy mill

2702. Sulphuric acid mist is arrested by using a ____________ scrubber?
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A. Venturi

B. Packed wet

C. Co-current

D. Hollow wet

2703. What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls ?
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A. 2.76

B. 1

C. 0.5

D. 0.66
2704. Range of compressibility co-efficient of the commercial compressible cake obtained in filtration operation is_____________________?
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A. 0.01 to 0.1

B. 0.2 to 0.8

C. 0.2 to 0.4

D. 0.1 to 0.3

2705. _____________ is the most commonly used filter aid?
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A. Semi-plastic clay

B. Vermiculite

C. Fullers earth

D. Diatomaceous earth
2706. A belt conveyor used for the transportation of materials can___________________?
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A. All A., B. and C.

B. Travel at a speed upto 300 metres/minute

C. Handle materials upto 5000 tons/hr

D. Run upto 1 km

2707. The basic filtration equation is given as dt/dV = (?/A ?P). [(? .CV/A) + Rm], where, V is volume of the filtrate; A is the filtration area, a is specific cake resistance, ? is viscosity of the filtrate, and C is the concentration of the solids in the feed slurry. In a 20 minutes constant rate filtration, 5 m3 of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m3 of filtrate to be produced? Neglect filter medium resistance, Rm; assume incompressible cake ?
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A. 25

B. 20

C. 30

D. 10

2708. _____________ are mixed using ribbon blenders ?
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A. Dry powders

B. Thick pastes

C. Lumpy solids and low viscosity liquids

D. High viscosity liquids

2709. Which of the following is not categorised as a mechanical operation?
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A. Humidification

B. Size enlargement

C. Agitation

D. Filtration

2710. Mixing of light fine powder such as insecticides is done by____________________?
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A. Banbury mixer

B. Pug mill

C. Impact wheels

D. Kneader

2711. Brunauer, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume & the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation ?
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A. Langmuirs assumption applies to every adsorbed layer

B. There is no dynamic equilibrium between successive layer

C. cept the first one) is involved in each of the evaporation process

D. The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer

E. None of these

2712. Size reduction does not occur due to compression in case of________________?
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A. Jaw crushers

B. Gyratory crushers

C. Rod mills

D. Smooth roll crushers

2713. Which of the following is not a cutting machine ?
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A. Slitters

B. Dicers

C. Knife cutters

D. Tube mills
2714. With increase in drum speed, in a rotary drum filter, the filtration rate_______________?
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A. Decreases

B. Increases linearly

C. Is not affected

D. Increases
2715. Wet sieving is employed, when the product contains ________________ materials?
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A. Non-sticky

B. Coarse

C. Abrasive

D. Large quantity of very fine
2716. The maximum slope of a belt conveyor can be_____________________?
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A. 60

B. 15

C. 45

D. 30
2717. In a roll crusher, the specific power consumption and the production rate is affected by the_________________?
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A. Reduction ratio

B. Differential roll speed

C. Both A. and B.

D. Neither A. nor B.

2718. The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bonds law, Rittingers law and Kicks law) depend upon the_________________?
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A. Feed material

B. Type of crushing machine

C. Both A. & B.

D. Neither A. nor B.

2719. The speed of a rotary drum vacuum filter may be about _____________ rpm?
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A. 1

B. 500

C. 100

D. 50

2720. For benefication of iron ore, the most commonly used method is______________?
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A. None of these

B. Flocculation

C. Froth floatation

D. Jigging & tabling
2721. Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately?
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A. None of these

B. Rittingers law

C. Bonds law

D. Kicks law

2722. The grinding in a hammer crusher takes place due to the_______________?
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A. Attrition

B. Impact

C. Both A. & B.

D. Neither A. nor B.

2723. A photochemical reaction is _______________ light?
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A. Used to convert heat energy into

B. Initiated by

C. Catalysed by

D. Accompanied with emission of

2724. The inlet pressure in a constant rate filtration____________________?
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A. Increases continuously

B. Remains constant

C. Decreases gradually

D. None of these

2725. Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of_____________________?
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A. Electromagnets

B. Unbalanced flywheels

C. Cams or eccentric shafts

D. Either A., B. or C.
2726. Filter aid is used to____________________?
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A. Decrease the pressure drop

B. Act as a support base for the septum

C. Increase the rate of filtration

D. Increase the porosity of the cake
2727. Sauter mean diameter is the same as the ______________ mean diameter?
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A. Geometric

B. Mass

C. Arithmetic

D. Volume-surface
2728. The cake resistance increases steadily with the time of filtration in a plate and frame filter employing constant ______________ filtration?
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A. Rate

B. Pressure

C. Both A. & B.

D. Neither A. nor B.

2729. For separation of sugar solution from settled out mud, we use a ___________________ filter?
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A. Centrifugal

B. Sparkler

C. Rotary drum vacuum

D. Plate and frame

2730. Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of__________________?
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A. Bronze

B. Concrete

C. Stainless steel

D. Flint or porcelain
2731. Short distance transportation of grain, gravel, sand, ash, asphalt etc. is done by using a ______________ conveyor?
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A. Screw

B. Slat or drag

C. Ribbon

D. Flight

2732. Production rate _____________ with increased fineness, with a given energy input to the size reduction machine?
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A. Increases

B. May increase or decrease; depends on the machine

C. Remains unchanged

D. Decreases
2733. For achieving maximum capacity of the ball mill, the ball charge should be equal to about ______________ percent of the ball mill volume?
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A. 10

B. 25

C. 50

D. 75

2734. Size reduction of _____________ is accomplished in steam heated rollers and roll crushers?
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A. Hard rubber

B. Waxes

C. Resins

D. Gums

2735. Which of the following is not accomplished by agitation of liquids in agitators ?
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A. Dispersing immiscible liquid in form of emulsion

B. Dispersing gas in liquid

C. Suspending solid particles

D. Blending of immiscible liquids
2736. Which of the following is the most suitable for cleaning of fine coal dust (<0.5 mm) ?
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A. Baum jig washer

B. Trough washer

C. Froth floatation

D. Spiral separator

2737. Reduction ratio of crushers is the___________________?
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A. None of these

B. Ratio of discharge opening to feed opening

C. Ratio of feed opening to discharge opening

D. Determining factor for minimum dia of the feed and the product

2738. The main size reduction operation in ultrafine grinders is_____________?
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A. Impact

B. Attrition

C. Cutting

D. Compression

2739. Ultra centrifuges are used for the separation of _____________ solid particles?
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A. Coarse

B. Dissolved

C. Colloidal

D. Fine

2740. In closed circuit grinding as compared to open circuit grinding, the_________________?
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A. Specific surface of product is more

B. Operation is economical

C. Product has lesser size uniformity

D. Production rate at a given limiting size is lower

2741. In bag filters, filter fabrics are never made of__________________?
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A. Metallic wire woven mesh

B. Polyester fibres

C. Cotton fibres

D. Nylon fibres

2742. Filter medium resistance is important during the ______________ of filtration?
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A. Early stages

B. None of these

C. Final stages

D. Entire process

2743. The process opposite to dispersion is termed as the___________________?
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A. Flocculation

B. Filtration

C. None of these

D. Sedimentation

2744. The capacity of a classifier in tons of solid/hr is given by (where, A = cross-sectional area in m2, V = rising velocity of fluid in m/sec, S = percentage of solids in the suspension by volume, ? = density of solids in kg/m3)_________________?
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A. 3.6 A.S. ?

B. 3.6 AVS/?

C. 3.6 A.V.?

D. 3.6 AVS.?

E. wer: Option

2745. Which of the following is a pressure filter ?
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A. Rotary drum filter

B. Plate and flame filter

C. Leaf filter (Moore filter)

D. Sand filter

2746. Choke crushing (in case of a Jaw crusher) compared to free crushing__________________?
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A. Results in increased capacity

B. Consumes less power

C. Consumes more power

D. Both A. and C.

2747. In an exothermic reaction, the energy of the reacting substances as compared to that of products is____________________?
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A. Either A. or B., depends on order of reaction

B. More

C. Less

D. Same

2748. Vibrating screens have capacity in the range of ______________ tons/ft2 .mm mesh size?
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A. 5 to 25

B. 100 to 250

C. 50 to 100

D. 0.2 to 0.8
2749. The conversion of a reactant, undergoing a first order reaction, at a time equal to three times the half life of the reaction is ?
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A. Data insufficient to calculate

B. 0.425

C. 0.5

D. 0.875
2750. In the fluid catalytic cracker (FCC), the cracking reaction is _____________ (i) and the regeneration is _______________ (ii) _______________?
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A. (i) endothermic (ii) endothermic

B. (i) exothermic (ii) exothermic

C. (i) exothermic (ii) endothermic

D. (i) endothermic (ii) exothermic