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.
| 801. |
Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscoisty above __________ poise. |
| A. | 300 |
| B. | 600 |
| C. | 1000 |
| D. | 1500 |
| Answer» C. 1000 | |
| 802. |
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. | |
| 803. |
Cylinderical shell thickness of rotary drier is generally __________ mm. |
| A. | 43526 |
| B. | 18-22 |
| C. | 43683 |
| D. | 42339 |
| Answer» D. 42339 | |
| 804. |
The function of manholes provided in the shell of a distillation column is to |
| A. | keep a check on the liquid gradient over the plate by direct visual observation. |
| B. | give access to the individual trays for cleaning, maintenance and installation. |
| C. | guard against foaming & entrainment by dumping antifoaming agent through it. |
| D. | all (a), (b) and (c). |
| Answer» C. guard against foaming & entrainment by dumping antifoaming agent through it. | |
| 805. |
The thermal stress in a metallic bar does not depend upon the |
| A. | changes in temperature. |
| B. | cross-sectional area. |
| C. | both (a) and (b). |
| D. | neither (a) nor (b). |
| Answer» C. both (a) and (b). | |
| 806. |
Two iron pipes of the same nominal diameter but different schedule numbers will have the same |
| A. | inside diameter |
| B. | outside diameter |
| C. | wall thickness |
| D. | none of these |
| Answer» B. outside diameter | |
| 807. |
Speed of industrial paddle agitator ranges from __________ rpm. |
| A. | 1 to 5 |
| B. | 20 to 100 |
| C. | 500 to 750 |
| D. | 1000 to 2000 |
| Answer» C. 500 to 750 | |
| 808. |
Back-trapping in a distillation column results due to |
| A. | low gas velocity. |
| B. | high gas velocity. |
| C. | excessive liquid gradient over the tray. |
| D. | low reflux ratio. |
| Answer» D. low reflux ratio. | |
| 809. |
Maximum plate efficiency is achieved in case of __________ flow. |
| A. | split |
| B. | cross |
| C. | cascade |
| D. | reverse |
| Answer» C. cascade | |
| 810. |
Correct use of 'factor of safety' is very important in equipment design. It is defined as the ratio of the |
| A. | ultimate stress to breaking stress. |
| B. | ultimate stress to working stress. |
| C. | working stress to ultimate stress. |
| D. | none of these. |
| Answer» C. working stress to ultimate stress. | |
| 811. |
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. | |
| 812. |
The ratio of the largest load in a test to the original cross-sectional area of the test specimen is called the __________ stress. |
| A. | yield point |
| B. | breaking |
| C. | ultimate |
| D. | none of these |
| Answer» D. none of these | |
| 813. |
To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of |
| A. | (1.2)3/2 |
| B. | (1.2)3/5 |
| C. | (1.2)2/3 |
| D. | (1.2)5/3 |
| Answer» E. | |
| 814. |
In a shell and tube heat exchanger, the 'tube pitch' is defined as the |
| A. | O.D. of the tube for square pitch. |
| B. | shortest distance between two adj acent tube holes. |
| C. | shortest centre to centre distance between adjacent tubes. |
| D. | none of these. |
| Answer» D. none of these. | |
| 815. |
In the design of a paddle agitator, the ratiois normally taken as |
| A. | 0.1 |
| B. | 0.8 |
| C. | 0.25 |
| D. | 0.5 |
| Answer» C. 0.25 | |
| 816. |
Floating head heat exchangers are used for the |
| A. | heat transfer between corrosive fluids. |
| B. | cases where temperature difference between the shell and the tubes is more (>50°C). |
| C. | co-current heat transfer systems. |
| D. | counter-current heat transfer systems. |
| Answer» C. co-current heat transfer systems. | |
| 817. |
Baffles may be eliminated for |
| A. | low viscosity liquids (< 200 poise). |
| B. | high viscosity liquids (> 600 poise). |
| C. | large diameter tanks. |
| D. | none of these. |
| Answer» C. large diameter tanks. | |
| 818. |
For identical situation, condensing film coefficient in case of a horizontal condenser is almost __________ the value expected in case of vertical condenser. |
| A. | half |
| B. | twice |
| C. | thrice |
| D. | five times |
| Answer» D. five times | |
| 819. |
With increase in the number of shell passes, the value of FT |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | remains same, only if the number of tube passes does not change. |
| Answer» B. decreases | |
| 820. |
Value of Peclet number = ‚àû, is the representative of$ |
| A. | laminar flow. |
| B. | complete back mixing, |
| C. | plug flow. |
| D. | eddy diffusivity = 0. |
| Answer» D. eddy diffusivity = 0. | |
| 821. |
A high vapour velocity is required for high plate efficiency in a seive plate coloumn. The satisfactory value of operating vapor velocity for design purpose in seive plate column is about __________ percent of the flooding velocity. |
| A. | 45 |
| B. | 60 |
| C. | 80 |
| D. | 95 |
| Answer» D. 95 | |
| 822. |
Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter. |
| A. | 1.5 to 2 |
| B. | 2.5 to 5 |
| C. | 5 to 10 |
| D. | 10 to 15 |
| Answer» C. 5 to 10 | |
| 823. |
In the allocated cap area, bubble caps are generally arranged on equilateral triangular pitch. Number of caps fixed on a plate is with a |
| A. | clearance of 25-75 mm. |
| B. | cap pitch of 1.3-2 times the cap diameter. |
| C. | either 'a' or 'b'. |
| D. | neither 'a' nor 'b'. |
| Answer» D. neither 'a' nor 'b'. | |
| 824. |
Pressure drop due to pipe fittings can be estimated by the equation, , where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (dimensionless) for 45° elbow and 180° close return bends would be respectively around |
| A. | 5 and 10 |
| B. | 45 and 75 |
| C. | 180 and 300 |
| D. | 300 and 500 |
| Answer» C. 180 and 300 | |
| 825. |
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. | |
| B. | D2 - D1 |
| C. | |
| D. | none of these |
| Answer» B. D2 - D1 | |
| 826. |
Baffle spacing is generally __________ the I.D. of the shell. |
| A. | more than |
| B. | not greater than |
| C. | not less than one fifth of |
| D. | both (b) and (c) |
| Answer» E. | |
| 827. |
In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cms. |
| A. | 10 |
| B. | 20 |
| C. | 30 |
| D. | 35 |
| Answer» B. 20 | |
| 828. |
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 | |
| 829. |
Minimum tube pitch recommended for shell and tube heat exchangers is about __________ times the outside diameter of the tube. |
| A. | 1.25 |
| B. | 1.75 |
| C. | 2.5 |
| D. | 3.5 |
| Answer» B. 1.75 | |
| 830. |
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 | |
| 831. |
Hazards associated with the relief valve leakage for extremely hazardous material storage can be taken care of by providing |
| A. | rupture diaphragm |
| B. | dikes |
| C. | surge chamber |
| D. | none of these |
| Answer» B. dikes | |
| 832. |
Cooling water fouling factors vary in the range of 0.001 to 0.003 |
| A. | (BTU/hr.ft2 . °F)-1 |
| B. | (kcal/hr.m2 .°C)-1 |
| C. | (W/m2.°K)-1 |
| D. | (kcal/hr. m. °C)-1 |
| Answer» B. (kcal/hr.m2 .¬∞C)-1 | |
| 833. |
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 | |
| 834. |
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) | |
| 835. |
Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is |
| A. | more |
| B. | same |
| C. | less |
| D. | twice |
| Answer» D. twice | |
| 836. |
In the agitators, the power required will be changed with the increase of diameter of agitator (D) as |
| A. | D2 |
| B. | D5 |
| C. | D |
| D. | D9 |
| Answer» C. D | |
| 837. |
The average velocity in the tubes of a 1-4 heat exchanger is __________ times that in 1-1 heat exchanger having the same size & number of tubes and operated at same liquid flow rate. |
| A. | 2 |
| B. | 43497 |
| C. | 4 |
| D. | 43556 |
| Answer» D. 43556 | |
| 838. |
For laminar flow (NRe < 2100) in steel pipe, the optimum inside pipe diameter is given by |
| A. | Di, opt = 3 Q0.36 ρ0.18 |
| B. | Di, opt = 3.9 Q0.45 . ρ0.23 |
| C. | Di, opt = 7.6 Q0.36 . ρ0.9 |
| D. | Di, opt = 3 Q0.36 . ρ1.86 μ0.08 |
| Answer» B. Di, opt = 3.9 Q0.45 . œÅ0.23 | |
| 839. |
Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the |
| A. | flow rates of each fluid. |
| B. | type and size of packing. |
| C. | concentration of each fluid. |
| D. | all a, b & c. |
| Answer» E. | |
| 840. |
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 | |
| 841. |
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. | |
| 842. |
Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger |
| A. | permits the use of less tubes in a given shell diameter. |
| B. | facilitates comparatively easier external cleaning because of large clearance. |
| C. | permits the use of more tubes in a given shell diameter. |
| D. | both (b) and (c). |
| Answer» D. both (b) and (c). | |
| 843. |
Generally, elliptical dished heads |
| A. | are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for pressure vessels operating above a pressure of 1.5 MN/m2 . |
| B. | resist half the pressure rating compared to hemi spherical head provided on the cylindrical shell of the same thickness and diameter. |
| C. | are approximately as strong as seamless cylindrical shell having the corresponding I.D and O.D. |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 844. |
In inclined long tube vertical evaporators, the tubes are inclined at an angle of |
| A. | 15° |
| B. | 90° |
| C. | 45° |
| D. | 60° |
| Answer» D. 60¬∞ | |
| 845. |
Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than __________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop. |
| A. | 25 |
| B. | 50 |
| C. | 75 |
| D. | 150 |
| Answer» D. 150 | |
| 846. |
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. | 43586 |
| B. | 20-40 |
| C. | 100-150 |
| D. | 1000-1500 |
| Answer» C. 100-150 | |
| 847. |
In perforated plate towers, the |
| A. | hole sizes may be around 1/8" or 3/16". |
| B. | total hole area may be around 6 to 15% of tower cross-sectional area. |
| C. | pressure drop is less compared is similar bubble cap towers. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 848. |
Pick out the wrong statement pertaining to the design of a horizontal tube evaporator. |
| A. | It is unsuitable for concentrating those liquids, which form a scale or deposit salt. |
| B. | It is suitable for process, in which the final product is a liquor instead of solid. |
| C. | Its usual dimensions are: tube dia = 2-3 cms; evaporator body dia = 1-4 metres and evaporator height = 2.5-4 metres. |
| D. | Liquor flows inside the tube, while the steam is outside submerging the tube. |
| Answer» E. | |
| 849. |
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 | |
| 850. |
Maximum allowable vapour velocity in a bubble cap tower is determined by the |
| A. | entrainment considerations. |
| B. | vapour density. |
| C. | diameter of the column. |
| D. | none of these. |
| Answer» B. vapour density. | |