chemical engineering MCQs – Page 114

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
2261. In constant pressure filtration ?
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A. Rate of filtration increases with time

B. Rate of filtration decreases with time

C. Rate of filtration is constant

D. Resistance decreases with time

2262. Solid particles of different densities are separated by _____________________?
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A. Filters

B. Thickness

C. Sorting classifier

D. Cyclones

2263. The most suitable equipment used to devulcanise rubber scrap and to make water dispersion & rubber solution is a __________________?
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A. Propeller agitator

B. Boundary mixer

C. Sharpies centrifuge

D. None of these

2264. Angle of nip of the crushing rolls does not depend upon the_______________?
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A. Product size

B. Feed size

C. Speed of the rolls

D. Diameter of the rolls

2265. The reduction ratio for grinders is defined as (where, Df and Dp are average diameters of feed and product respectively) ?
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A. Dp/Df

B. Df/Dp

C. None of these

D. Df Dp

2266. The binary diffusivity in gases does not depend upon the ___________________?
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A. Temperature

B. Pressure

C. Nature of the components

D. None of these
2267. Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is________________?
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A. > 100

B. < 100

C. < 10

D. > 10

2268. Length/diameter ratio of a ball mill is __________________ ?
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A. 1

B. > 1

C. 1.5

D. < 1
2269. For sizing of fine materials, the most suitable equipment is a____________________?
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A. Vibrating screen

B. Shaking screen

C. Trommel

D. Grizzly

2270. What is the reduction ratio in a fine crushing operation having following feed and product sizes ?
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A. 5

B. 10

C. 2

D. 0.5

2271. Critical Speed (Nc) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively) ?
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A. Nc = (1/4?). ?(g/R1 R2)

B. Nc = (1/2?). ?(R1 R2/g)

C. Nc = (1/2?). ?(g/R1 R2)

D. Nc = (1/?). ?(g/R1 R2)

2272. Grinding efficiency of a ball mill is of the order of _______________ percent?
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A. 1-5

B. 75-80

C. 40-50

D. 90-95

2273. The most common packing used in industrial operations is _______________ rings?
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A. Single spiral

B. Cross-partition

C. Lessing

D. Raschig
2274. Fluid energy mill comes in the category of________________?
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A. Grinder

B. Ultrafine grinder

C. Cutter

D. Crusher

2275. The opening of a 200 mesh screen (Taylor series) is__________________?
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A. 0.0074 mm

B. 0.0047 cm

C. 0.0074 cm

D. 74 milli-microns

2276. Pine oil used in froth floatation technique acts as a/an_____________________?
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A. Collector

B. Modifier

C. Frother

D. Activator

2277. Activators are those chemicals which help buoying up one mineral in preference to the other in the froth floatation process. Which of the following is an activator ?
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A. Cresylic acid

B. Copper sulphate

C. Sodium carbonate

D. Calcium carbonate

2278. In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of _______________ crushing?
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A. Primary

B. Ultrafine

C. Fine

D. Secondary

2279. The main differentiation factor between tube mill and ball mill is the ___________________?
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A. Size of the grinding media

B. Operating speed

C. Length to diameter ratio

D. Final product size

2280. Maximum size reduction in a ball mill is done by the, ______________ action?
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A. Attrition

B. Cutting

C. Compression

D. Impact