chemical engineering MCQs – Page 372

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 Review each marked answer and report any item that may be outdated or unclear.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

7421. Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about _____________ percent?
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A. < 8

B. < 5

C. < 2

D. < 10

7422. In a furnace employing forced draught as compared to induced draught______________________?
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A. Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced

B. None of these

C. Positive pressure exists in the furnace

D. The fan operates hot and hence blades are liable to corrosion and erosion

7423. Scaling of furnace stock is reduced by _______________ in flue gas?
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A. H2

B. All A., B. & C.

C. High CO/CO2

D. CO

7424. In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of_________________?
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A. Preheating the primary air

B. Transportation of coal

C. Drying of coal

D. Combustion of coal by supplying it around the burner

7425. Pick out the wrong statemen?
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A. Hardening makes the steel more brittle

B. High alloy steels contain more than 50% alloying element

C. 18/8 stainless steel is a magnetic steel

D. Both B. and C.

7426. Presence of SO2 in furnace gases attacks the ferrous metal by way of_________________?
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A. Attacking the grain boundaries; particularly severe on low carbon and nickel bearing steels at

B. h temperature

C. All A., B. and C.

D. Causing metal embrittlement

E. Accelerating the rate of scaling

7427. Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above _____________ C, because corrosion prevails at higher temperatures?
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A. 750

B. 1050

C. 1250

D. 350

7428. Thermal efficiency of blast furnace stoves used for heating blast (air) may be about _____________ percent?
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A. 20

B. 60

C. 80

D. 40

7429. Aluminium alloy is one of the most suitable materials of construction for aircrafts mainly due to its___________________?
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A. High strength to weight ratio

B. Its ability to be cast, rolled, forged & stamped

C. High strength and corrosion & oxidation-resistance at elevated temperature

D. Low temperature strength properties

7430. Pick out the wrong statement?
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A. A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity

B. Laminar flow of viscous liquids is involved in the lubrication of various types of bearings

C. tribution</strong>

D. Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes

E. Newtons law of viscosity is not applicable to the turbulent flow of fluid with linear velocity

7431. In drop forging process, the forging is done by dropping the _____________ at high velocity?
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A. Hammer

B. Weight on hammer

C. Die with hammer

D. Workpiece

7432. The range of Mhos scale of hardness is from________________?
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A. 1 to 15

B. 1 to10

C. 0 to 10

D. 1 to 8

7433. ______________ is not a case hardening process?
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A. Carburising

B. Cyaniding

C. Nitriding

D. Annealing

7434. Soap kettle used in the production of laundry soap is made of____________________?
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A. Steel with top section nickel clad or stainless steel

B. Cast iron

C. Concrete

D. Nickel

7435. Pick out the wrong statement?
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A. The eddy viscosity is a fluid property

B. The eddy viscosity is a function of the type of turbulence involved

C. The viscosity of a liquid increases with decrease in temperature

D. The viscosity of gas increases with increase in temperature

7436. Which metal is protected by the layer of its own oxide ?
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A. Iron

B. Aluminium

C. Calcium

D. Silver

7437. Pick out the wrong statement?
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A. ghness & Reynolds number

B. Friction losses in pipe fittings are generally expressed in terms of velocity heads

C. Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer

D. Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative

E. Blowers develop a maximum pressure of 2 atmospheres

7438. The maximum percentage of chromium that can be added to steel is about____________________?
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A. 24

B. 12

C. 30

D. 18

7439. Which of the following heat treatment processes is used for softening the hardened material ?
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A. None of these

B. Annealing

C. Tempering

D. Normalising

7440. Locomotive boiler tubes are made of _____________ alloys?
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A. Magnesium

B. Nickel

C. Arsenic copper

D. Aluminium

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