MCQOPTIONS
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MCQOPTIONS
This section includes 908 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Value of Peclet number = ∞, is the representative of |
| A. | Laminar flow |
| B. | Complete back mixing |
| C. | Plug flow |
| D. | Eddy diffusivity = 0 |
| Answer» D. Eddy diffusivity = 0 | |
| 202. |
The centre to centre distance between two consecutive baffles in a shell and tube heat exchanger is called the baffle pitch or baffle spacing, which is more than 1/5th the I.D. of the shell. Which of the following is not a function of the baffles? |
| A. | To increase the residence time of shell side fluid |
| B. | To provide support to the tube bundle |
| C. | To reduce the induced vibration in the tubes |
| D. | To increase the tube side heat transfer co-efficient by inducing turbulence |
| Answer» E. | |
| 203. |
Le/D for fully open globe value may be around |
| A. | 10 |
| B. | 25 |
| C. | 75 |
| D. | 300 |
| Answer» E. | |
| 204. |
What is the slope of the operating line in the rectifying section of a distillation coloumn? |
| A. | 0 |
| B. | ∞ |
| C. | > 1 |
| D. | <1 |
| Answer» E. | |
| 205. |
A claming section before the liquid flows into the downcomer is privided to |
| A. | Permit release of entrained vapour in the liquid |
| B. | Reduce the discharge fluctuation |
| C. | Ensure better vapour-liquid contact |
| D. | Cool the liquid before it flows down |
| Answer» B. Reduce the discharge fluctuation | |
| 206. |
Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer). |
| A. | 250 |
| B. | 450 |
| C. | 650 |
| D. | 750 |
| Answer» D. 750 | |
| 207. |
With increase in gas flow rate to fabric surface area ratio (Nm³/hr/m² fabric surface area), the size & the cost of a bag filter |
| A. | Increases |
| B. | Decreases |
| C. | Remain unaffected |
| D. | None of these |
| Answer» C. Remain unaffected | |
| 208. |
What is the slope of the operating line in the stripping section of a distillation column? |
| A. | 0 |
| B. | ? |
| C. | > 1 |
| D. | < 1 |
| Answer» D. < 1 | |
| 209. |
A perforated plate has holes of diameter dh arranged in a pitch ph. Each hole has a tube of I.D. dt passing through it. The ligament efficiency is given by |
| A. | (ph - dh)/ph |
| B. | (ph - dh . dt/2)/ph |
| C. | (ph - dt)/ph |
| D. | (ph - dh)/dh |
| Answer» D. (ph - dh)/dh | |
| 210. |
Which of the following efficiencies can be greater than 100%? |
| A. | Overall plate efficiency |
| B. | Murphree plate efficiency |
| C. | Point efficiency |
| D. | None of these |
| Answer» C. Point efficiency | |
| 211. |
In a double pipe concentric heat exchanger, the equivalent diameter of annulus for heat transfer would be (where, D₁ and D₂ are I.D. of inner and outer pipes) |
| A. | (D₂² - D₁²)/D₁² |
| B. | D₂ - D₁ |
| C. | (D₂² - D₁²)/D₂² |
| D. | None of these |
| Answer» B. D₂ - D₁ | |
| 212. |
Which of the following types of reactors is the safest from operation point of view? |
| A. | A vapor phase reactor |
| B. | Pot type reactor |
| C. | A liquid phase reactor |
| D. | A liquid phase catalytic reactor |
| Answer» B. Pot type reactor | |
| 213. |
Friction factor for turbulent flow in a new pipe is given by |
| A. | f = 16/NRe |
| B. | f = 0.04/NRe0.16 |
| C. | f = 0.22 NRe0.05 |
| D. | f = 25/NRe |
| Answer» C. f = 0.22 NRe0.05 | |
| 214. |
Which of the following packing materials provides for maximum mass transfer? |
| A. | Lessig rings |
| B. | Raschig rings |
| C. | Cross-partition rings |
| D. | All of the above |
| Answer» D. All of the above | |
| 215. |
Heat transfer co-efficient, hG(Kcal/hr.m² .°C) and mass velocity of air, G (kg/hr.m² ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to |
| A. | HG = 1.004G0.37 |
| B. | 1.004G0.8 |
| C. | HG = 0.0176G0.37 |
| D. | 0.0176G1.37 |
| Answer» B. 1.004G0.8 | |
| 216. |
A cylinderical pressure vessel of volume 6 πm³ has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm² and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to |
| A. | 5 mm |
| B. | 6 mm |
| C. | 8 mm |
| D. | 10 mm |
| Answer» E. | |
| 217. |
Which of the following factors determine the amount of entrainment in a distillation column? |
| A. | Plate spacing |
| B. | Depth of liquid above the bubble cap slots |
| C. | Vapour velocity in the volume between the plates |
| D. | All of the above |
| Answer» E. | |
| 218. |
What is the value of 'q' for saturated liquid feed to a distillation column? |
| A. | 0 |
| B. | <1 |
| C. | 1 |
| D. | >1 |
| Answer» D. >1 | |
| 219. |
What is the slope of the feed line, if the feed to a distillation column is a saturated liquid? |
| A. | 0 |
| B. | ∞ |
| C. | > 1 |
| D. | < 1 |
| Answer» C. > 1 | |
| 220. |
Le/D for a Tee (used as elbow, entering branch) would be |
| A. | Less than that for Tee (used as elbow, entering run) |
| B. | More than that for Tee (used as elbow, entering run) |
| C. | Around 90 |
| D. | Both B and C |
| Answer» E. | |
| 221. |
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m².°C. |
| A. | 1250 |
| B. | 2500 |
| C. | 7500 |
| D. | 15000 |
| Answer» D. 15000 | |
| 222. |
In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area) |
| A. | Aa = Sa |
| B. | 1.2 Aa = 1.2 Sa |
| C. | Sa = 1.5 Aa |
| D. | Aa = 1.5 Sa |
| Answer» B. 1.2 Aa = 1.2 Sa | |
| 223. |
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, σ = yield strength and E = modulus of elasticity) |
| A. | E |
| B. | Σ |
| C. | Σ/E |
| D. | E/σ |
| Answer» D. E/σ | |
| 224. |
The absorption factor is defined as (where, S₁ = slope of the equilibrium curve, S₂ = slope of the operating line) |
| A. | S₁/S₂ |
| B. | S₁.S₂ |
| C. | S₂/S₁ |
| D. | 1/S₁.S₂ |
| Answer» B. S₁.S₂ | |
| 225. |
Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi) |
| A. | Η = 17 - 61.1 log μ |
| B. | Η = 24.6 (Δp/μ) |
| C. | Η = 1.66 - 0.25 log μ |
| D. | Η = 0.25 log μ - 1.67 |
| Answer» B. Η = 24.6 (Δp/μ) | |
| 226. |
In a cylinderical vessel subjected to internal pressure, the longitudinal stress σL and the circumferential stress, σh are related by |
| A. | σh = 2 σL |
| B. | σh = σL |
| C. | σh = σL/2 |
| D. | No relation exists |
| Answer» B. σh = σL | |
| 227. |
What is the value of 'q' for saturated vapor feed to a distillation column ?(where q = fraction of the feed stream that is liquid.)%! |
| A. | 0 |
| B. | 1 |
| C. | <0 |
| D. | > 1 |
| Answer» B. 1 | |
| 228. |
In a bag filter, the pressure drop increases directly as the%! |
| A. | Density of the gas, but is independent of the viscosity of the gas |
| B. | Density of the gas and inversely as viscosity of the gas |
| C. | Viscosity of the gas and inversely as density of the gas |
| D. | None of these |
| Answer» C. Viscosity of the gas and inversely as density of the gas | |
| 229. |
At the following point for a given packing and set of fluids, the pressure drop per metre of packed height, with variation in fluid rates and operating pressure%! |
| A. | Increases |
| B. | Decreases |
| C. | Remains same |
| D. | May increase or decrease depending upon the solubility of the gas in the liquid |
| Answer» D. May increase or decrease depending upon the solubility of the gas in the liquid | |
| 230. |
What is the slope of the feed line, if the feed to a distillation column is a saturated liquid?%! |
| A. | 0 |
| B. | ‚à û |
| C. | > 1 |
| D. | < 1 |
| Answer» C. > 1 | |
| 231. |
In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the%! |
| A. | Liquid gradient on the tray |
| B. | Lower skirt clearance |
| C. | Lower static submergence |
| D. | Small downcomer liquid seal |
| Answer» B. Lower skirt clearance | |
| 232. |
The clearance between two tubes in a shell and tube heat exchanger is known as 'ligament', whose minimum value is __________ the outside diameter of the tube, but in no case it should be less than 4.5 mm.%! |
| A. | Equal to |
| B. | Half |
| C. | One fourth |
| D. | Three fourth |
| Answer» D. Three fourth | |
| 233. |
Flanges are connected to pipes by%! |
| A. | Screwing |
| B. | Welding |
| C. | Brazing |
| D. | All of the above |
| Answer» E. | |
| 234. |
The maximum liquid gradient over a tray must not exceed%! |
| A. | 0.5" -1.25" |
| B. | 2"-3.5" |
| C. | 5" |
| D. | Half the tray spacing |
| Answer» B. 2"-3.5" | |
| 235. |
A claming section before the liquid flows into the downcomer is privided to%! |
| A. | Permit release of entrained vapour in the liquid |
| B. | Reduce the discharge fluctuation |
| C. | Ensure better vapour-liquid contact |
| D. | Cool the liquid before it flows down |
| Answer» B. Reduce the discharge fluctuation | |
| 236. |
Nominal size of a pipe is an indication of its __________ diameter.%! |
| A. | Inner |
| B. | Outer |
| C. | Approximate |
| D. | None of these |
| Answer» D. None of these | |
| 237. |
Pick out the wrong statement pertaining to the design of a basket type evaporator.%! |
| A. | It is used for high viscosity liquor having large rate of scaling |
| B. | The tube bundle is suspended on bracket |
| C. | There is no central downtake |
| D. | Downtake is formed by the annular space between the bundle and the shell |
| Answer» B. The tube bundle is suspended on bracket | |
| 238. |
Commercial packed scrubbers are normally designed for a pressure drop range of __________ mm water coloumn per metre of packed height.%! |
| A. | 4-8 |
| B. | 17-34 |
| C. | 52-68 |
| D. | 88-105 |
| Answer» C. 52-68 | |
| 239. |
Joint efficiency (J) for a seamless pipe is%! |
| A. | 1 |
| B. | 0.85 |
| C. | 1.2 |
| D. | < 0.5 |
| Answer» B. 0.85 | |
| 240. |
A shell may by termed as thin if its thickness to diameter ratio is less than 0.1. The factor which can be neglected in the calculation of membrane stresses is%! |
| A. | Bending |
| B. | Deformation |
| C. | Shear |
| D. | Elongation |
| Answer» B. Deformation | |
| 241. |
Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm.%! |
| A. | 0.1 to 2 |
| B. | 5 to 7 |
| C. | 3 to 8 |
| D. | 8 to 15 |
| Answer» B. 5 to 7 | |
| 242. |
Pick out the wrong statement pertaining to the design of a long tube vertical evaporator.%! |
| A. | Tube dia is 3-6 cms, while tube length in 3-6 metres |
| B. | Steam is fed to the shell, whereas the liquor is filled inside the tube |
| C. | Liquor level is maintained at l/3rd to 1/2 of the height of the tube |
| D. | None of these |
| Answer» E. | |
| 243. |
In case of design of a shell and tube heat exchanger,%! |
| A. | Minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch |
| B. | Minimum tube sheet thickness (in which tubes are fixed) is equal to the O.D. of the tube upto 15 mm tube diameter; and for > 15 mm tube diameter, tube sheet thickness is smaller than tube diameter |
| C. | O.D. of the tube is 6 to 40 mm while the tube lengths used are 0.5, 2.5, 3.0, 4.0, 5.0, 6 metres |
| D. | All of the above |
| Answer» E. | |
| 244. |
Any shell opening greater than 5 cms for a storage tank must be reinforced for reason of%! |
| A. | Preventing the local overstressing of the shell around the opening |
| B. | Reduction of discontinuity in shape at the junction |
| C. | Making the joint leak proof |
| D. | None of these |
| Answer» B. Reduction of discontinuity in shape at the junction | |
| 245. |
In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for%! |
| A. | Reducing scale deposition |
| B. | Increasing pressure drop |
| C. | Fixing the tubes |
| D. | Creating turbulence |
| Answer» E. | |
| 246. |
Skirt support is the most suitable for supporting __________ vessels.%! |
| A. | Small horizontal |
| B. | Large horizontal |
| C. | Tall vertical |
| D. | Thick walled |
| Answer» D. Thick walled | |
| 247. |
In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds.%! |
| A. | 1 |
| B. | 8 |
| C. | 80 |
| D. | 180 |
| Answer» C. 80 | |
| 248. |
*$_Any shell opening greater than 5 cms for a storage tank must be reinforced for reason of? |
| A. | Preventing the local overstressing of the shell around the opening |
| B. | Reduction of discontinuity in shape at the junction |
| C. | Making the joint leak proof |
| D. | None of these |
| Answer» B. Reduction of discontinuity in shape at the junction | |
| 249. |
*$_Skirt support is the most suitable for supporting __________ vessels.? |
| A. | Small horizontal |
| B. | Large horizontal |
| C. | Tall vertical |
| D. | Thick walled |
| Answer» D. Thick walled | |
| 250. |
*$_In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds.? |
| A. | 1 |
| B. | 8 |
| C. | 80 |
| D. | 180 |
| Answer» C. 80 | |