chemical engineering Mcqs
4451. If air (a non-condensing gas) is present in a condensing vapor stream, it will ______________ the condensation rate of vapor?
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A. Increase

B. Decrease

C. Increase the condensing film co-efficient as well as

D. Not affect

4452. The ratio of kinematic viscosity to thermal diffusivity is called the _______________ number?
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A. Stanton

B. Nusselt

C. Peclet

D. Prandtl
4453. Pick out the wrong statement?
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A. Unit of thermal conductance is W/K

B. None of these

C. Thermal conductance of a wall of thickness L, thermal conductivity k and heat flow area A is kL/A

D. Reciprocal of the resistance to heat flow is called thermal conductance

4454. Maximum alumina content in high alumina refractory can be as high as ____________ percent?
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A. 70

B. 50

C. 90

D. 30

4455. Pick out the wrong statement?
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A. The joint made by overlapping of one plate over the other, and then riveting the two plates together with two rows of rivets is called double riveted butt joint

B. Riveting provides a permanent fastening method

C. The efficiency of a riveted joint is the ratio of the strength of the riveted joint to the strength of the solid plate

D. Shank diameter of the rivets should be less than the size of the hole drilled in the plate for riveting

4456. Enthalpy of a vapor gas mixture may be increased by increasing the________________?
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A. Temperature at constant humidity

B. All A., B. & C.

C. Temperature and the humidity

D. Humidity at constant temperature

4457. A vapor whose partial pressure is less than its equilibrium vapor pressure is called a ______________ vapor?
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A. Supersaturated

B. Saturated

C. Superheated

D. None of these

4458. ____________ chart is known as transient heat conduction chart?
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A. Cox

B. Dirhings

C. Molliers

D. Heislers

4459. The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50C in industrial practice mainly to avoid_________________?
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A. Uneconomic LMTD

B. Its evaporation loss

C. Excessive corrosion

D. Decrease in heat exchanger efficiency

4460. Refractory bricks with lower permeability is produced by using _________________?
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A. All A., B. and C.

B. Finer grog size

C. Higher moulding pressure

D. Higher firing temperature

4461. Heat of ____________ of a fuel is called its calorific value?
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A. Formation

B. Combustion

C. Reaction

D. Vaporisation

4462. Pick out the wrong statement ?
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A. Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient

B. Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

C. In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles

D. S.I. unit of fouling factor is Watt/m2.K
4463. Magnesite refractories are generally not used in the__________________?
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A. Steel melting furnace

B. Burning zone of cement kilns

C. Open hearth furnace

D. Electric furnace walls

4464. Avogadros number is equal to__________________?
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A. 6.023 1026 molecules/gm.mole

B. 6.023 1023 molecules/kg.mole

C. 6.023 1023 molecules/gm.mole

D. 6.023 1016 molecules/kg.mole

4465. Pick out the wrong statement ?
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A. Solvates are chemical compounds formed by solute with their solvents. When water is the

B. Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted

C. al tube cross-sectional area

D. p; sub-cooling

E. In heat exchanger calculations (?t) weighted is used in place of ?t, when it involves more

F. In case of short tube vertical evaporators, area of central downtake is about 50 to 100% of the

4466. Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by__________________?
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A. Conduction

B. Convection

C. Eddies current

D. None of these

4467. The purpose of floating head in a heat exchanger is to_________________?
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A. Provide support for tubes

B. Decrease the pressure drop

C. Avoid buckling of tubes

D. Facilitate its lengthening, if needed

4468. Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?
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A. Partial ionisation

B. High viscosity

C. Low density

D. Dense structure

4469. In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is_________________?
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A. Infinity

B. Zero

C. Minimum

D. Maximum

4470. Pick out the wrong statement?
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A. Split ring type and pull through type floating heads are two commonly used floating heads is

B. t exchangers

C. Orifice baffles are never used in a shell and tube heat exchanger

D. Pressure drop on the shell side of a heat exchanger depends upon tube pitch also

E. In a horizontal tube evaporator, surface blanketing by air is avoided

4471. Kinematic viscosity of 1 m2 /second is equivalent to _____________ stokes?
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A. 102

B. 10

C. 104

D. 103

4472. The number of water molecules present in a drop of water weighing 0.018 gm is 6.023 __________?
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A. 1023

B. 1026

C. 1019

D. 1020
4473. Panel test determines the ______________ of refractories?
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A. Refractoriness under load (RUL)

B. Slag penetration resistance

C. Spalling resistance

D. Fusion point

4474. Pick out the wrong statement about the recycle stream in a process ?
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A. ntity of the same reactant entering the process as fresh feed is called combined feed ratio

B. Recycling in a process does not help in getting higher extent of reaction

C. ntain the quantity of liquid within the column

D. Recycling is exemplified by refluxing back a part of the distillate to the distillation column to

E. Recycling in a process stream helps in utilising the valuable reactants to the maximum with

F. imum loss of reactants

4475. Controlling heat transfer film co-efficient is the one, which offers ______________ resistance to heat transfer?
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A. No

B. The largest

C. Lower

D. The least

4476. Molality is defined as the number of gm moles of solute per _____________ of solvent?
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A. kg

B. Litre

C. gm

D. gm.mole

4477. Crystallisation of solids from a homogeneous solution is a/an ______________ process?
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A. Mildly endothermic

B. None of these

C. Exothermic

D. Highly endothermic

4478. Pick out the wrong statement ?
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A. Heat transfer from a hot body to cold body by the emission of heat waves is called radiation

B. None of these

C. Filmwise condensation takes place on non-wettable surfaces

D. The boiling point of a solution is affected by liquid head as well as boiling point elevation

4479. The unit of specific heat at constant pressure, Cp, in SI unit is__________________?
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A. J/m3K

B. W/mK

C. J/kgK

D. W/m2C

4480. Which of the following is insensitive to changes in pressure ?
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A. Heat of vaporisation

B. Melting point

C. Heat of fusion

D. Both B. and C.
4481. Pick out the wrong statement ?
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A. Economy of a multiple effect evaporator is not influenced by the boiling point elevation

B. ditions of temperature</strong>

C. Two identical cubes of iron and copper will have the same heat content under the same

D. Finned tube heat exchangers are suitable for heating air by steam

E. Double pipe heat exchangers are mostly used in the field of refrigeration

4482. Boiling point elevation of a solution of NaOH _____________________?
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A. Increases rapidly with temperature rise

B. Is almost independent of temperature

C. Is almost independent of pressure

D. Both B. and C
4483. The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by_______________?
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A. Forced convection

B. Steady state conduction

C. Natural convection

D. Transient conduction
4484. Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DV?/?)0.8 (CP.?/k)0.4. This is valid for the value of NRe equal to_______________?
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A. 4000

B. > 10000
4485. For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?
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A. hf > hd

B. hf = hd

C. hf < hd

D. hf could be greater or smaller than hd

4486. Thermal diffusivity is the most important in heat transfer by__________________?
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A. Conduction

B. Natural convection

C. Radiation

D. Condensation

4487. In physical adsorption, as compared to chemisorption, the________________________?
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A. Heat of adsorption is very large

B. Quantity adsorbed per unit mass is higher

C. Activation energy is very high

D. Rate of adsorption is controlled by the resistance to surface reaction

4488. Lower wall courses of soaking pits are made of _____________ bricks to avoid the action of molten slag & scale?
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A. Low duty fireclay

B. Silicon carbide

C. Silica

D. Chrome or magnesite
4489. Concentration of a solution expressed in terms of _______________ is independent of temperature?
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A. Normality

B. Molarity

C. None of these

D. Molality
4490. Chemically, mullite refractories is________________?
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A. ThO2

B. Al2O3

C. 3Al2O3.2SiO2

D. ZrSO4

4491. Which of the following is concerned with both heat and mass transfer ?
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A. Kutateladze number

B. Lewis relationship

C. Froude number

D. Nusselt number

4492. Quartz is__________________?
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A. All A., B. and C.

B. Converted to Tridymite on firing between 870 to 1470C

C. Stable form of silica upto 870C

D. Transformed to Cristobalite on heating above 1470C

4493. A 2-4 heat exchanger involves__________________?
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A. Only counter-flow of fluids

B. Only parallel-flow of fluids

C. Both counter and parallel-flow of the fluids

D. Smaller pressure drop compared to 1-2 exchanger

4494. For any system, the _____________ heat of solution is dependent on the temperature and the adsorbate concentration?
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A. Integral

B. Differential

C. Both A. & B.

D. Neither A. nor B.

4495. A diathermanous substance _______________ the thermal radiation completely?
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A. Reflects

B. None of these

C. Absorbs

D. Transmits
4496. Fireclay refractories___________________?
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A. All A., B. and C.

B. Combine with salts (e.g. chlorides sulphates etc.) & bases (e.g. lime, magnesia etc.) forming

C. ible aluminates silicates etc

D. Are not resistant to the action of basic slags

E. Shrink during firing

4497. The gravimetric (i.e., by weight) composition of a vapor saturated gas is independent of the_______________?
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A. Nature of both the gas & the liquid

B. Temperature

C. Total pressure

D. None of these
4498. Pick out the wrong statement. In an agitated vertical cylindrical reaction vessel, the___________________?
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A. Filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period

B. Dished bottom vessel has very high power consumption

C. Ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1

D. Flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids

4499. Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900C ) use, except______________?
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A. Fusion point

B. Thermal conductivity

C. Electrical conductivity

D. Cost
4500. Baffles are provided in heat exchangers to increase the________________?
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A. Heat transfer area

B. Heat transfer rate

C. Heat transfer co-efficient

D. Fouling factor