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.
| 501. |
In a heat exchanger, shell side fluid velocity can be changed by changing the tube? |
| A. | Layout |
| B. | Pitch |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» D. Neither A nor B | |
| 502. |
The type of stress developed in a metallic bar on subjecting it to a change in temperature without allowing it to be deformed is __________ stress.? |
| A. | Shear |
| B. | Tensile |
| C. | Compressive |
| D. | Thermal |
| Answer» E. | |
| 503. |
In the downcomer of a distillation column, the minimum recommended residence time is about __________ seconds.? |
| A. | 2.5 |
| B. | 5 |
| C. | 12.5 |
| D. | 17.5 |
| Answer» C. 12.5 | |
| 504. |
In a pressure vessel containing multiple openings of various dimensions at different parts, stress concentration at the edges of the opening is maximum which becomes negligibly small beyond the area covered by __________ times the hole diameter.? |
| A. | Two |
| B. | Five |
| C. | Ten |
| D. | Twenty |
| Answer» B. Five | |
| 505. |
Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column.? |
| A. | Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates |
| B. | Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the bubble cap |
| C. | Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features |
| D. | Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range |
| Answer» D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range | |
| 506. |
If 'D' is the inside diameter of the shell of a shell and tube heat exchanger, then the baffle spacing is usually in the range of? |
| A. | D/2 or minimum 2" to 5D |
| B. | D/5 or minimum 2" to 5D |
| C. | D/5 or minimum 2" to D |
| D. | None of these |
| Answer» C. D/5 or minimum 2" to D | |
| 507. |
The raio, (properller agitator dia/tank dia) is normally taken as? |
| A. | 0.15-030 |
| B. | 0.5-0.65 |
| C. | 0.75-0.85 |
| D. | 0.60-0.90 |
| Answer» B. 0.5-0.65 | |
| 508. |
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 | |
| 509. |
Pick out the wrong statement about the design of a sieve plate column.? |
| A. | An increased weir height improves the tray efficiency at the cost of high plate pressure drop; optimum wear height being 40-90 mm for column pressure above atmospheric and 6-12 mm for vacuum columns |
| B. | For segmental downcomers, the chord length is 60-80% of the column diameter. An initial value of downcomer area of 12% is taken in the design |
| C. | Width of the calming section provided at the inlet and outlet sides of the plate is 75 mm for column diameter below 1.5 metres and 100 mm for larger diameter columns |
| D. | Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds |
| Answer» E. | |
| 510. |
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 | |
| 511. |
Cylinderical shell thickness of rotary drier is generally __________ mm.? |
| A. | 2-3 |
| B. | 18-22 |
| C. | 6-8 |
| D. | 12-15 |
| Answer» D. 12-15 | |
| 512. |
Ratio of tube length to shell diameter for a shell and tube heat exchanger is? |
| A. | 8 : 1 to 12 : 1 for both liquid-liquid and gas-gas heat exchangers |
| B. | 4 : 1 to 8 : 1 for liquid-liquid exchanger |
| C. | < 4 : 1 for gas-gas exchangers |
| D. | Both B & C |
| Answer» E. | |
| 513. |
Maximum plate efficiency is achieved in case of __________ flow.? |
| A. | Split |
| B. | Cross |
| C. | Cascade |
| D. | Reverse |
| Answer» C. Cascade | |
| 514. |
Of the pressure vessels, with same thickness but different diameters, which one withstands higher pressure?? |
| A. | Larger dia vessel |
| B. | Smaller dia vessel |
| C. | Larger dia long vessel |
| D. | Strength of the vessel is same irrespective of the diameter |
| Answer» C. Larger dia long vessel | |
| 515. |
Rivets are generally specified by the? |
| A. | Head diameter |
| B. | Shank diameter |
| C. | Overall length |
| D. | None of these |
| Answer» C. Overall length | |
| 516. |
Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle?? |
| A. | Segmental baffle |
| B. | Flat plate extending across the wall |
| C. | Disk type baffle |
| D. | Helical type baffle |
| Answer» C. Disk type baffle | |
| 517. |
Maximum acceptable total liquid gradient over a tray is about __________ mm.? |
| A. | 5.5 |
| B. | 12.5 |
| C. | 30.5 |
| D. | 45.5 |
| Answer» C. 30.5 | |
| 518. |
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 | |
| 519. |
The equivalent diameter for pressure drop is __________ that for heat transfer.? |
| A. | Smaller than |
| B. | Greater than |
| C. | Equal to |
| D. | Not related with |
| Answer» E. | |
| 520. |
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. ≈í√≥ = 24.6 (≈í√Æp/≈í¬∫) | |
| 521. |
For a given design of bubble cap, the number of bubble caps to be used per tray is set by the? |
| A. | Allowable gas velocity through the slots |
| B. | Plate spacing |
| C. | Diameter of the column |
| D. | All of the above |
| Answer» B. Plate spacing | |
| 522. |
Lap joints are preferred for plates having thickness __________ mm.? |
| A. | < 12.5 |
| B. | > 3 |
| C. | > 5 |
| D. | 5-10 |
| Answer» C. > 5 | |
| 523. |
Which of the following lengths of heat exchanger tubes are normally not used in practice? |
| A. | 2.5 metres |
| B. | 6 metres |
| C. | 10 metres |
| D. | 0.5 metre |
| Answer» D. 0.5 metre | |
| 524. |
In a shell and tube heat exchanger having triangular pitch, the shell side equivalent diameter is given by |
| A. | 4(0.86p² - πd²/4)/πd |
| B. | (p² - πd²/4)/πd |
| C. | 4(0.86p² - πd²)/πd |
| D. | (4p² - πd²/4)/πd |
| Answer» B. (p¬¨‚⧠- ≈ì√Ñd¬¨‚â§/4)/≈ì√Ñd | |
| 525. |
Le/D for a Tee (used as elbow, entering run) would be around |
| A. | 5 |
| B. | 60 |
| C. | 200 |
| D. | 350 |
| Answer» C. 200 | |
| 526. |
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 | |
| 527. |
In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres ρ = apparent solid density, kg/m³ L = flow rate of dry solids, kg/see. m² drier cross-section H = hold up of solid.)$ |
| A. | Z.H.ρ/L |
| B. | L/Z.H.ρ |
| C. | H.ρ/L |
| D. | Z.H/L.ρ |
| Answer» B. L/Z.H.≈ì√Ö | |
| 528. |
Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate? |
| A. | Triangular pitch |
| B. | Square pitch |
| C. | Diagonal square pitch |
| D. | Heat transfer rate is independent of tube arrangement |
| Answer» B. Square pitch | |
| 529. |
In the design of a paddle agitator, the ratio (paddle dia/tank dia) is normally taken as |
| A. | 0.1 |
| B. | 0.8 |
| C. | 0.25 |
| D. | 0.5 |
| Answer» C. 0.25 | |
| 530. |
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/≈ì√â | |
| 531. |
In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-10 times the column diameter, whichever is less. Maximum size of the pall rings should not exceed __________ of the column diameter. |
| A. | 1/10-1/15th |
| B. | 1/5-1/10th |
| C. | 1/20-1/30th |
| D. | 1/2 to 1/4th |
| Answer» B. 1/5-1/10th | |
| 532. |
Hoop (circumferential) stress induced in a thin walled 'Horton Sphere' used for the storage of liquid ammonia under pressure is |
| A. | pD/2t |
| B. | pD/4t |
| C. | pD/3t |
| D. | pD/6t |
| Answer» B. pD/4t | |
| 533. |
Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe-Thiele's method? |
| A. | Sensible heat changes for vapour & liquid are negligibly small |
| B. | Reflux is not a saturated liquid |
| C. | Molar latent heat of the two components are equal |
| D. | Heat of mixing of normal liquid is assumed to be zero |
| Answer» C. Molar latent heat of the two components are equal | |
| 534. |
Value of Peclet number = ‚à û, is the representative of# |
| A. | Laminar flow |
| B. | Complete back mixing |
| C. | Plug flow |
| D. | Eddy diffusivity = 0 |
| Answer» D. Eddy diffusivity = 0 | |
| 535. |
The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.# |
| A. | 2 |
| B. | 5 |
| C. | 10 |
| D. | 15 |
| Answer» C. 10 | |
| 536. |
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. ≈ì√âh = ≈ì√âL | |
| 537. |
For a cylinderical internally pressurised vessel, which of the following closure types would withstand highest pressure, if each closure is of the same material and thickness? |
| A. | Hemispherical |
| B. | Ellipsoidal (2 : 1) |
| C. | Conical |
| D. | Flat plate |
| Answer» C. Conical | |
| 538. |
The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about __________ mm of water column per metre height of packing. |
| A. | 1-5 |
| B. | 20-40 |
| C. | 100-150 |
| D. | 1000-1500 |
| Answer» C. 100-150 | |
| 539. |
Width and depth of grooves in the tube sheet holes normally are __________ inch respectively. |
| A. | 1/8 and 1/64 |
| B. | 1/64 and 1/8 |
| C. | 1/2 and 8 |
| D. | 1/2 and 5 |
| Answer» B. 1/64 and 1/8 | |
| 540. |
Which of the following is the most common type of baffle used in industrial shell and tube heat exchanger? |
| A. | 75% cut segmental baffle |
| B. | 25% cut segmental baffle |
| C. | Orifice baffle |
| D. | Disk and doughnut baffle |
| Answer» C. Orifice baffle | |
| 541. |
For pipe flows, head is proportional to __________ at constant capacity (where D = pipe diameter ). |
| A. | 1/D |
| B. | 1/D² |
| C. | 1/D⁵ |
| D. | D² |
| Answer» D. D¬¨‚⧠| |
| 542. |
Le/D for 90° elbow (medium radius) and 90°square elbow would be respectively around# |
| A. | 25 and 60 |
| B. | 3 and 5 |
| C. | 100 and 250 |
| D. | 250 and 600 |
| Answer» B. 3 and 5 | |
| 543. |
Practical dividing line between a ductile and brittle materials is suggested, when the ultimate elongation is about 5%. Generally, larger the knuckle radius, stronger is the corner torus section of a head. The knuckle radius provided should be less than __________ of the head. |
| A. | 6% of I.D. |
| B. | 3 times the thickness |
| C. | either (a) or (b), whichever is larger |
| D. | either (a) or (b), whichever is smaller |
| Answer» D. either (a) or (b), whichever is smaller | |
| 544. |
For turbine agitator, the impeller diameter is about |
| A. | 0.3 to 0.5 d |
| B. | 0.1 to 0.2 d |
| C. | 0.65 to 0.85 d |
| D. | 0.95 d |
| Answer» B. 0.1 to 0.2 d | |
| 545. |
for a Tee (used as elbow, entering run) would be around |
| A. | 5 |
| B. | 60 |
| C. | 200 |
| D. | 350 |
| Answer» C. 200 | |
| 546. |
In a distillation column, bubble caps are located on trays with a pitch of __________ times the outside diameter of the caps. |
| A. | 1.3 to 2 |
| B. | 1.6 to 2 |
| C. | 2.5 |
| D. | 1.5 to 3 |
| Answer» B. 1.6 to 2 | |
| 547. |
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 | |
| 548. |
The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is |
| A. | pd/2t |
| B. | pd/4t |
| C. | pd/t |
| D. | pd/8t |
| Answer» C. pd/t | |
| 549. |
With increase in pressure drop (for a given particle size), the dust collection efficiency of a cyclone separator will |
| A. | increase |
| B. | decrease |
| C. | remain unaffected |
| D. | increase or decrease depending on the nature of the dust. |
| Answer» B. decrease | |
| 550. |
In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes |
| A. | are easier to clean. |
| B. | are less prone to fouling. |
| C. | can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less. |
| D. | none of these. |
| Answer» D. none of these. | |