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.
| 851. |
The wall thickness of thin cylindrical shell with hemispherical ends is __________ that of the spherical ends. |
| A. | equal to |
| B. | more than |
| C. | less than |
| D. | either (b) or (c); depends on maximum permissible internal pressure |
| Answer» C. less than | |
| 852. |
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 (a), (b) & (c). |
| Answer» E. | |
| 853. |
The dust collection efficiency of a cyclone separator |
| A. | decreases with increase in gas flow rate. |
| B. | is inversely proportional to the mass of the dust particle. |
| C. | is directly proportional to the radius of the dust particle path. |
| D. | none of these. |
| Answer» E. | |
| 854. |
Thickness of the frame of a plate and frame filter as compared to that of plates is |
| A. | less |
| B. | same |
| C. | more |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 855. |
Tube height in a calendria type evaporator is normally less than __________ metres. |
| A. | 1 |
| B. | 2 |
| C. | 3.5 |
| D. | 5.5 |
| Answer» C. 3.5 | |
| 856. |
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 | |
| 857. |
The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally __________ the tube wall thickness. |
| A. | equal to |
| B. | twice |
| C. | four times |
| D. | half |
| Answer» C. four times | |
| 858. |
A 'rupture disc' is provided in chemical equipments as an accessory meant for |
| A. | relieving excess pressure. |
| B. | creating turbulence. |
| C. | enhancing mixing rate. |
| D. | avoiding vortex formation. |
| Answer» B. creating turbulence. | |
| 859. |
Pick out the wrong statement.In an agitated vertical cylinderical reaction vessel, the |
| A. | ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1. |
| B. | filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period. |
| C. | flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids. |
| D. | dished bottom vessel has very high power consumption. |
| Answer» E. | |
| 860. |
Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation? |
| A. | Sorel-Lewis method. |
| B. | McCabe-Thiele's method. |
| C. | Ponchon-Savarit method. |
| D. | none of these. |
| Answer» B. McCabe-Thiele's method. | |
| 861. |
Steam economy is defined as the amount of evaporation per unit amount of steam used, while the capacity is the total evaporation obtained per hour. Use of multiple effect in evaporation |
| A. | increases capacity. |
| B. | increases economy. |
| C. | does not affect the capacity. |
| D. | both 'b' & 'c'. |
| Answer» E. | |
| 862. |
Pick out the wrong statement pertaining to the design of the distillation column. |
| A. | Generally, a skirt clerance of 0.5" to 1.5' is recommended to prevent plugging of the slots by residue build up. |
| B. | The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles. |
| C. | If sufficient slot area is not provided, the gas may pass through the skirt clearance. |
| D. | none of these. |
| Answer» E. | |
| 863. |
Joint efficiency (J) for a seamless pipe is |
| A. | 1 |
| B. | 0.85 |
| C. | 1.2 |
| D. | < 0.5 |
| Answer» B. 0.85 | |
| 864. |
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. | |
| 865. |
In a shell and tube heat exchanger having square pitch, the shell side equivalent diameter is given by (where, P = pitch, d = outside diameter of the tube) |
| A. | |
| B. | |
| C. | |
| D. | πd/4P2 |
| Answer» B. | |
| 866. |
A cylindrical storage tank can have a self supported conical roof, |
| A. | if its diameter is less than 15-20metres. |
| B. | if its diameter is more than 50 meters. |
| C. | if the thickness of the roof is more than that of the cylindrical shell. |
| D. | irrespective of its diameter. |
| Answer» B. if its diameter is more than 50 meters. | |
| 867. |
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. | |
| 868. |
At equal mass velocities, the values of film co-efficients for gases as compared to that for liquids are generally. |
| A. | higher |
| B. | lower |
| C. | same |
| D. | unpredictable |
| Answer» C. same | |
| 869. |
A binary liquid azeotropic mixture has boiling point higher than either of the components, when it shows __________ deviation from Raoult's Law. |
| A. | positive |
| B. | negative |
| C. | no |
| D. | none of these |
| Answer» C. no | |
| 870. |
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 | |
| 871. |
The operating pressure drop range in a bag filter is about __________ mm water gauge. |
| A. | 50-150 |
| B. | 43743 |
| C. | 500-1500 |
| D. | 1500-2500 |
| Answer» B. 43743 | |
| 872. |
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. | |
| C. | η = 1.66 - 0.25 log μ |
| D. | η = 0.25 log μ - 1.67 |
| Answer» B. | |
| 873. |
In a shell and tube heat exchanger, triangular pitch arrangement as compared to square pitch arrangement |
| A. | results in higher shell side pressure drop. |
| B. | can accomodate less number of tubes for a given shell diameter. |
| C. | facilitates easier shell side cleaning; hence is more suitable for handling high dirt factor shell side fluid. |
| D. | creates relatively lower turbulence on the shell side resulting in lower shell side heat transfer co-efficient. |
| Answer» B. can accomodate less number of tubes for a given shell diameter. | |
| 874. |
The main purpose of providing stepping on the trays is to |
| A. | increase the residence time. |
| B. | decrease the pressure drop. |
| C. | facilitate handling of large flow rate of liquid. |
| D. | improve the flow condition. |
| Answer» D. improve the flow condition. | |
| 875. |
Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate. |
| A. | 2 |
| B. | 43497 |
| C. | 4 |
| D. | 8 |
| Answer» E. | |
| 876. |
Longitundinal stress induced in a thin walled cylindrical storage vessel is |
| A. | |
| B. | |
| C. | |
| D. | |
| Answer» C. | |
| 877. |
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. | |
| 878. |
The shell side pressure drop in a shell and tube heat exchanger is maximum for __________ baffle. |
| A. | disk and ring |
| B. | segmental |
| C. | orifice |
| D. | independent of the type of |
| Answer» D. independent of the type of | |
| 879. |
Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about __________ percent. |
| A. | 5 |
| B. | 20 |
| C. | 35 |
| D. | 55 |
| Answer» C. 35 | |
| 880. |
A stuffing box is used for |
| A. | absorbing the contraction/expansion of pipeline due to temperature changes. |
| B. | prevention of fluid leakage around moving parts. |
| C. | facilitating smooth opening and closing of a valve. |
| D. | reducing the resistance of fluid flow. |
| Answer» C. facilitating smooth opening and closing of a valve. | |
| 881. |
For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter. |
| A. | 1 to 1.5 |
| B. | 2.5 to 3.5 |
| C. | 4 to 5 |
| D. | 6 to 8 |
| Answer» B. 2.5 to 3.5 | |
| 882. |
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 | |
| 883. |
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 | |
| 884. |
Optimum economic pipe diameter for fluid flow is determined by the |
| A. | viscosity of the fluid. |
| B. | density of the fluid. |
| C. | total cost considerations (pumping cost plus fixed cost of the pipe). |
| D. | none of these. |
| Answer» D. none of these. | |
| 885. |
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. | |
| 886. |
A rivetted joint does not fail by __________ of rivets. |
| A. | tearing |
| B. | shearing |
| C. | tearing of the plate across a row |
| D. | none of these |
| Answer» E. | |
| 887. |
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 (a), (b) and (c). |
| Answer» B. plate spacing. | |
| 888. |
__________ tower is the most suitable gas-liquid contacting device involving highly corrosive fluids. |
| A. | Sieve plate |
| B. | Packed |
| C. | Bubble cap plate |
| D. | None of these |
| Answer» C. Bubble cap plate | |
| 889. |
Liquid/petroleum fuel storage tanks are built underground (as in case of petrol pumps), when the storage capacity is less than __________ kilolitres. |
| A. | 20 |
| B. | 30 |
| C. | 45 |
| D. | 85 |
| Answer» D. 85 | |
| 890. |
__________ tray arrangement is recommended for distillation column having diameter upto 4 ft. |
| A. | Radial flow |
| B. | Cross flow |
| C. | Split flow |
| D. | Cascade |
| Answer» C. Split flow | |
| 891. |
The ratio of shear stress to shear strain is called |
| A. | bulk modulus |
| B. | shear modulus |
| C. | modulus of rigidity |
| D. | modulus of elasticity |
| Answer» C. modulus of rigidity | |
| 892. |
Pick out the wrong statement pertaining to the design of the bubble cap tray of a distillation column to give stable operation and even vapour distribution. |
| A. | The pressure drop due to the caps & slots and the static submergence should be as high as practicable for reasonable operation. |
| B. | Tendency towards stable operation is increased by increasing the skirt clearance of the caps, lowering the rate of liquid flow per unit plate width or increasing the spacing between the caps. |
| C. | The dimensionless ratio of liquid gradient to pressure drop head caused by the bubble cap assembly should be less than 0.4. |
| D. | none of these. |
| Answer» E. | |
| 893. |
Power required for agitation depends upon the |
| A. | height & properties of the liquid. |
| B. | agitator type & speed of agitation. |
| C. | size of agitator & the tank. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 894. |
In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm. |
| A. | 43588 |
| B. | 43774 |
| C. | 42217 |
| D. | 43435 |
| Answer» C. 42217 | |
| 895. |
Needle valves are generally not used for |
| A. | very large diameter pipes. |
| B. | high pressure throttling service. |
| C. | very accurate flow control. |
| D. | smaller sizes of pipe. |
| Answer» B. high pressure throttling service. | |
| 896. |
In chemical process equipments, the conical bottom heads used, usually has an apex angle of |
| A. | 20° |
| B. | 40° |
| C. | 60° |
| D. | 80° |
| Answer» D. 80¬∞ | |
| 897. |
25 per cent cut segmental baffle means that the baffle |
| A. | height is 75% of the I.D. of the shell. |
| B. | height is 25% of the I.D. of the shell. |
| C. | spacing is 75% of its height. |
| D. | width is 25% of its height. |
| Answer» B. height is 25% of the I.D. of the shell. | |
| 898. |
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 | |
| 899. |
for fully open globe value may be around |
| A. | 10 |
| B. | 25 |
| C. | 75 |
| D. | 300 |
| Answer» E. | |
| 900. |
Which of the following material is seldom used for pressure vessel construction ? |
| A. | Rimmed still |
| B. | Mild steel |
| C. | Killed steel |
| D. | Semi-killed steel |
| Answer» B. Mild steel | |