chemical engineering MCQs – Page 214

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 Review each marked answer and report any item that may be outdated or unclear.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

4261. Test piece for determination of RUL of a refractory is heated in a/an__________________?
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A. Neutral atmosphere

B. Oxidising atmosphere

C. Reducing atmosphere

D. Electric furnace

4262. Pick out the wrong statement?
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A. Super saturation of the solution is the driving potential for a crystal growth

B. The first stage of crystal formation is called nucleation

C. Swenson-Walker crystalliser is a batch crystalliser

D. The liquor left after the removal of crystals from a solution is called mother liquor

4263. The vapor pressure of liquids (having similar chemical nature) at any specified temperature ______________ with increasing molecular weight?
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A. Increases

B. Decreases

C. Increases linearly

D. Remains unchanged

4264. The heat capacity of a solid compound is calculated from the atomic heat capacities of its constituent elements with the help of the___________________?
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A. Antoine equation

B. Kopps rule

C. Kistyakowsky equation

D. Troutons rule

4265. In which mode of heat transfer, the Biot number is important ?
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A. Forced convection

B. Natural convection

C. Radiation

D. Transient heat conduction

4266. Measurement of the amount of dry gas collected over water from volume of moist gas is based on the___________________?
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A. Avogadros hypothesis

B. Charles law

C. Boyles law

D. Daltons law of partial pressures

4267. The heat evolved in the combustion of benzene is represented by the equation: C6H6 + 7.5 O2 = 6CO2 + 3H2O, ?H = 3264.6 kJ/kg. mole The heat energy change, when 39 gm of C6H6 is burnt in an open container, will be _____________ kJ/kgmole?
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A. -2448.45

B. -1632.3

C. 1632.3

D. 816.15

4268. Saturated molal absolute humidity of the vapor-gas mixture depends upon the______________________?
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A. Vapor pressure at dry bulb temperature

B. Total pressure

C. Both A. and B.

D. Neither A. nor B.

4269. Pick out the wrong statement?
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A. Ratio of its capacity to economy equals the steam consumption in kg/hr in an evaporator

B. Thermal conductivity of a dry material is more than that of the damp material

C. Vaporisation of organic substances in evaporator mostly causes foam formation

D. Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling

4270. Baffles in the shell side of a shell and tube heat exchanger ?
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A. Decrease the shell side heat transfer co-efficient

B. Increase the shell side heat transfer co-efficient

C. Force the liquid to flow parallel to the bank

D. Increase the cross-section of the shell side liquid

4271. Pick out the wrong statement?
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A. Refractoriness under load (RUL) of a refractory is always less than its refractoriness

B. Refractories used in muffle furnace should have low thermal conductivity

C. For reducing spalling tendency, the refractory should be well fired and its porosity should be more

D. The electrical resistivity of refractories drops rapidly with rise in temperature

4272. For a perfectly transparent surface (like gases), the____________________?
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A. Reflectivity = 0

B. Transmissivity = 1

C. Absorptivity = 0

D. All A., B. & C.

4273. Pick out the wrong statement/
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A. The emissivity of a surface decreases, if it gets corroded by atmospheric environment

B. The emissivity of a polished surface is quite low

C. The emissivity of a surface increases with increase in surface roughness

D. The emissivity of a non-metallic surface decreases with increase in the temperature

4274. Pick out the wrong statement?
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A. avelength of 0.5 ?1</strong>

B. wavelength band between 3 ?m to 4 ?m. The fraction of this energy in the total energy

C. The maximum is the emissive power of a surface at a temperature T1 occurs at a wavelength

D. In process heat exchangers, saturated steam is preferred over the superheated steam

E. tted over the entire wavelength range is equal to emissivity

F. A body at 925 K emits an energy of 1.42 x 1011?W/m2 (? is the Stefan-Boltzmann constant) in

4275. For a neutral solution (pH = 7), the value of [H+] [OH-] is equal to_________________?
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A. 0

B. 1

C. 1

4276. Which is not an acidic refractory ?
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A. Fireclay

B. Silica

C. Carbon black

D. High alumina refractory

4277. Applicability of Clausius-Clapeyron Equation is subject to the condition that the __________________?
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A. Vapor follows ideal gas law

B. Volume in the liquid state is negligible

C. Both A. & B.

D. Neither A. nor B.

4278. Steam condensate is recovered by steam traps and recycled for use as boiler feed water, because of its low___________________?
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A. Dissolved solids content

B. All A., B. and C.

C. Hardness

D. Suspended solids content

4279. Pick out the wrong statement?
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A. The Colburn jH factor for heat transfer is given by Nst Npr

B. Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection

C. The Peclet number is a measure of the ratio of energy transport by convection to that by conduction

D. The ratio NNu/NRe . Npr is called the Stanton number

4280. One micron is equal to _____________ cm?
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A. 10-4

B. 2-Oct

C. 6-Oct

D. 8-Oct

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