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.
| 751. |
Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling. |
| A. | CO2 |
| B. | SO2 |
| C. | NH3 |
| D. | none of these |
| Answer» D. none of these | |
| 752. |
In case of 1.5" heat exchanger tubes, the inside flow area __________ with decrease in BWG. |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | none of these |
| Answer» C. remains same | |
| 753. |
For given number of passes, pitch & tube diameter, the maximum number of tubes that can be accommodated in a shell of tripled inside diameter will be __________ times. |
| A. | about 9 |
| B. | considerably more than 9 |
| C. | considerably less than 9 |
| D. | about 3 |
| Answer» C. considerably less than 9 | |
| 754. |
Pick out the wrong statement pertaining to 'Horton sphere' used for the storage of liquid ammonia. |
| A. | Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column. |
| B. | Thickness of spherical shell is half that of the cylinderical vessel under same operating pressure condition. Besides, the ratio of surface area to volume is less for sphere than any other shape ; hence insulation required is less. |
| C. | Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2 . |
| D. | Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 . |
| Answer» E. | |
| 755. |
What is the slope of the feed line, if the feed to a distillation column is a saturated liquid ? |
| A. | 0 |
| B. | ‚àû |
| C. | > 1 |
| D. | < 1 |
| Answer» C. > 1 | |
| 756. |
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. | |
| 757. |
In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference |
| A. | is always less than arithmetic average value. |
| B. | is always more than arithmetic mean value and the geometric mean value. |
| C. | is always less than arithmetic mean value, but more than geometric mean value. |
| D. | may be either more or less than geometric mean and arithmetic mean value depending upon whether the flow of stream is co-current or counter-current. |
| Answer» B. is always more than arithmetic mean value and the geometric mean value. | |
| 758. |
In a vertical short tube evaporator (Calendria type), the |
| A. | tube dia of 2.5-7.5 cms, tube length of 75-200 cms and cylinderical drum dia of 1-6 metres are normally used. |
| B. | area of central downtake is equal to 40 to 100% of total cross-sectional area of the surrounding tube. |
| C. | liquor is inside the tube while the steam is outside the tube. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 759. |
Liquid gradient over the tray results due to the |
| A. | resistance offered to flow of liquids by caps & risers and the flow of gas. |
| B. | low gas velocity. |
| C. | large plate spacing. |
| D. | large reflux ratio. |
| Answer» B. low gas velocity. | |
| 760. |
In seive plate column, holes are drilled or punched in sizes ranging from 2.5 to 12 mm (5 mm being widely used). The hole pitch is normally __________ times the hole diameter to give the required hole area. |
| A. | 0.5 to 1.5 |
| B. | 2.5 to 4.0 |
| C. | 5 to 10 |
| D. | 10 to 15 |
| Answer» C. 5 to 10 | |
| 761. |
Movement of pipeline caused by thermal expansion is taken care by providing |
| A. | expansion joint. |
| B. | changes in its direction. |
| C. | change in the shape of pipeline. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 762. |
What is the minimum recommended ligament for square pitch arrangement in case of heat exchangers ? |
| A. | 6.5 cms |
| B. | 6.5 mm |
| C. | Equal to tube I.D |
| D. | Equal to tube O.D |
| Answer» C. Equal to tube I.D | |
| 763. |
A binary liquid azeotropic mixture has boiling point lower than either of the components, when it shows __________ deviation from Raoult's Law. |
| A. | positive |
| B. | negative |
| C. | no |
| D. | none of these |
| Answer» B. negative | |
| 764. |
The necessary wall thickness for a metallic storage vessel is a function of the |
| A. | ultimate tensile strength (or yield point) of the material and operating temperature. |
| B. | operating pressure and welding/joint efficiency. |
| C. | diameter of the vessel. |
| D. | all (a); (b) and (c). |
| Answer» E. | |
| 765. |
Seamless pipe is made |
| A. | from rolled strips formed into cylinders and seam-welded. |
| B. | by extrusion & casting into static and centrifugal molds. |
| C. | by forging a solid round, piercing it by simultaneously rotating & forcing it over a piercer point and further reducing it by rolling gas drawing. |
| D. | both (b) and (c). |
| Answer» E. | |
| 766. |
Vapor velocity in a distillation column for non-foaming mixture is in the range of __________ times the flooding velocity. |
| A. | 0.1 to 0.3 |
| B. | 0.6 to 0.7 |
| C. | 0.85 to 0.95 |
| D. | 1.5 to 2 |
| Answer» C. 0.85 to 0.95 | |
| 767. |
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 | |
| 768. |
An underdesigned steam trap will |
| A. | waste steam. |
| B. | destroy itself of acceleration wear due to rapid recycling. |
| C. | back up condensate and cause water hammer in steam line. |
| D. | none of these. |
| Answer» D. none of these. | |
| 769. |
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. | |
| 770. |
Theoretically calculated diameter of the stripping section of the continuous rectification column is __________ that of the enriching section. |
| A. | less than |
| B. | more than |
| C. | same as |
| D. | either more or less (depending upon relative volatility) |
| Answer» C. same as | |
| 771. |
1.2 to 3.8 cms is the value of the |
| A. | downcomer liquid seal in case of a balanced tray design. |
| B. | static submergence in case of a bubble cap tray for column operating under pressure (‚â• 1 atm.). |
| C. | skirt clearance for bubble caps. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 772. |
Scale up problem in design based on the similarity concept takes into account __________ similarity. |
| A. | geometrical |
| B. | kinematic |
| C. | dynamic |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 773. |
The buckling tendency of compression members is always in the direction of the |
| A. | least radius of gyration. |
| B. | axis of the load. |
| C. | perpendicular to the axis of the load. |
| D. | none of these. |
| Answer» B. axis of the load. | |
| 774. |
An increase in the liquid resistance to interphase mass transfer and a resultant reduction in plate efficiency is caused by |
| A. | an increase in liquid viscosity. |
| B. | an increase in relatived volatility for rectification columns. |
| C. | decrease in gas solubility for absorbers. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 775. |
A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to the |
| A. | central dished section and corner torus section. |
| B. | corner torus section and central dished section. |
| C. | central dished section and straight flange section. |
| D. | straight flange section and corner torus section. |
| Answer» B. corner torus section and central dished section. | |
| 776. |
Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the |
| A. | practical limit reached, due to low heat transfer rate because of inadequate temperature difference. |
| B. | economic limit reached, when the plant cost exceeds the saving of steam. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 777. |
Apex angle of conical heads used in the bottom heads of chemical process equipments is usually |
| A. | 30° |
| B. | 45° |
| C. | 60° |
| D. | 75° |
| Answer» D. 75¬∞ | |
| 778. |
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 | |
| 779. |
Vertical vessels are not supported by |
| A. | brackets |
| B. | skirts |
| C. | columns |
| D. | saddles |
| Answer» E. | |
| 780. |
Bubble cap plate column is |
| A. | a finite stage contactor. |
| B. | used only for distillation, not for absorption. |
| C. | a differential stage contactor. |
| D. | a continuous contactor. |
| Answer» B. used only for distillation, not for absorption. | |
| 781. |
In a distillation column, minimum clearance to be maintained betweeen the overflow weir and the last row of the bubble caps is __________ cms. |
| A. | 2.5 |
| B. | 7.5 |
| C. | 15 |
| D. | 20 |
| Answer» C. 15 | |
| 782. |
Value of Peclet number = 0, is the representative of |
| A. | laminar flow. |
| B. | complete back mixing. |
| C. | plug flow. |
| D. | eddy diffusivity = 0. |
| Answer» C. plug flow. | |
| 783. |
The stress developed in a material without any permanent set is called the |
| A. | ultimate stress |
| B. | yield stress |
| C. | elastic limit |
| D. | breaking stress |
| Answer» D. breaking stress | |
| 784. |
Lug support is |
| A. | the most suitable for thick vertical vessel. |
| B. | same as bracket support. |
| C. | provided usually for vessels of much smaller height than skirt supported vessels. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 785. |
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 | |
| 786. |
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. | |
| 787. |
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. | |
| 788. |
It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than |
| A. | 0.99 |
| B. | 0.95 |
| C. | 0.8 |
| D. | 0.55 |
| Answer» D. 0.55 | |
| 789. |
In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to |
| A. | ‚àû |
| B. | 1 |
| C. | 20.8 |
| D. | 2 |
| Answer» C. 20.8 | |
| 790. |
The minimum tray spacing in distillation column of diameter less than 3 ft is normally __________ inches. |
| A. | 6 |
| B. | 18 |
| C. | 24 |
| D. | 34 |
| Answer» B. 18 | |
| 791. |
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. | |
| 792. |
Wall thickness of schedule 40 pipe as compared to that of schedule 80 pipe is |
| A. | more |
| B. | less |
| C. | same |
| D. | cither (a) or (b); depends upon the I.D. of the pipe |
| Answer» C. same | |
| 793. |
A pressure vessel is said to be made of 'thick' shell, if the ratio of its diameter to wall thickness is |
| A. | 10 |
| B. | 10 |
| C. | 20 |
| D. | 20 |
| Answer» B. 10 | |
| 794. |
Pressure drop (Δp) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as$ |
| A. | Δp = G |
| B. | Δp = G0.5 |
| C. | Δp = G2 |
| Answer» D. | |
| 795. |
Accidents in chemical plants are mostly due to |
| A. | inadequate equipment design. |
| B. | faulty operating procedures. |
| C. | improper layout of the equipments. |
| D. | failure of equipments. |
| Answer» C. improper layout of the equipments. | |
| 796. |
Larger depth of liquid on the trays of a distillation column |
| A. | leads to high tray efficiency. |
| B. | results in higher pressure drop per tray. |
| C. | both (a) & (b). |
| D. | neither (a) or (b). |
| Answer» D. neither (a) or (b). | |
| 797. |
__________ of water makes it a widely used coolant in heat exchangers. |
| A. | Low corrosiveness |
| B. | Low dirt factor |
| C. | High specific heat |
| D. | Low viscosity |
| Answer» D. Low viscosity | |
| 798. |
For a 25 mm hole drilled in plates to be rivetted, the shank diameter of the rivet should be __________ mm. |
| A. | 25 |
| B. | 23 |
| C. | 26 |
| D. | 27 |
| Answer» C. 26 | |
| 799. |
The retention time of material in a rotary dryer depends upon its |
| A. | rpm |
| B. | slope & length |
| C. | flights arrangement |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 800. |
Bracket supports are the most suitable for supporting __________ vessels. |
| A. | thick walled vertical |
| B. | horizontal |
| C. | thin shperical (e.g. Horton sphere) |
| D. | none of these |
| Answer» B. horizontal | |