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MCQOPTIONS
This section includes 8247 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 2051. |
Rate of adsorption increases as the |
| A. | temperature increases. |
| B. | temperature decreases. |
| C. | pressure decreases. |
| D. | size of adsorbent increases. |
| Answer» C. pressure decreases. | |
| 2052. |
Pick out the system with maximum boiling azeotrope at 1 atm. |
| A. | acetone chloroform |
| B. | ethyl alcohol-water |
| C. | benzene-ethyl alcohol |
| D. | none of these |
| Answer» B. ethyl alcohol-water | |
| 2053. |
As the reflux ratio, in a continuous counter-current extraction is increased, the number of stages |
| A. | increase |
| B. | decrease |
| C. | remain unchanged |
| D. | can either increase or decrease, depends on the system |
| Answer» C. remain unchanged | |
| 2054. |
In triangular co-ordinates, the ternery composition point falls __________ of the triangle. |
| A. | in the corners |
| B. | inside |
| C. | on the sides |
| D. | none of these. |
| Answer» C. on the sides | |
| 2055. |
In a single stage extraction process, 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction xf = 0.2. The mixture splits into an extract phase E and a raf-finate phase R containing A at xB = 0.5 and xR = 0.05 respectively. The total mass of the extract phase is (in Kg) |
| A. | 6.89 |
| B. | 8.89 |
| C. | 10 |
| D. | 8.25 |
| Answer» C. 10 | |
| 2056. |
Reboiler is considered as one theoretical plate, because |
| A. | of the assumption that vapour and liquid leaving the reboiler are in equilibrium. |
| B. | vapour is recycled to the column. |
| C. | reboiler itself contains one plate. |
| D. | none of these. |
| Answer» B. vapour is recycled to the column. | |
| 2057. |
For experimental determination of mass transfer co-efficient by wetted wall tower, the mass transfer area is |
| A. | calculated |
| B. | unknown |
| C. | known |
| D. | not required |
| Answer» D. not required | |
| 2058. |
In stripping section of continuous distillation column, the |
| A. | liquid is stripped of high boiler. |
| B. | liquid is enriched with high boiler. |
| C. | vapour is stripped of low boiler. |
| D. | none of these. |
| Answer» C. vapour is stripped of low boiler. | |
| 2059. |
Which of the following provides maximum contact surface for a liquid-vapour system? |
| A. | Packed tower |
| B. | Bubble-cap plate column |
| C. | Seive-plate column |
| D. | Wetted wall column |
| Answer» B. Bubble-cap plate column | |
| 2060. |
Most important factor to be considered in the selection of packings for absorbers is the __________ of packing. |
| A. | size |
| B. | durability |
| C. | porosity |
| D. | cost |
| Answer» D. cost | |
| 2061. |
__________ is the separation technique used for desalination of sea water. |
| A. | Thermal diffusion |
| B. | Reverse osmosis |
| C. | Adsorption |
| D. | absorption |
| Answer» C. Adsorption | |
| 2062. |
The relative saturation of a partially saturated mixture of vapour and gas can be increased by __________ of the mixture. |
| A. | reducing the total pressure |
| B. | increasing the total pressure |
| C. | reducing the temperature |
| D. | both (b) and (c) |
| Answer» E. | |
| 2063. |
Danckwerts developed the __________ theory. |
| A. | penetration |
| B. | surface renewal |
| C. | film |
| D. | none of these |
| Answer» C. film | |
| 2064. |
In rectifying section of a continuous distillation column, the |
| A. | vapour is enriched with low boilers. |
| B. | vapour is enriched with high boilers. |
| C. | liquid is stripped of high boilers. |
| D. | none of these. |
| Answer» C. liquid is stripped of high boilers. | |
| 2065. |
During constant rate drying period, vaporisation rate per unit drying surface area |
| A. | decreases with time. |
| B. | increases with time. |
| C. | does not change with time, |
| D. | does not affect the moisture content of the wet solid. |
| Answer» D. does not affect the moisture content of the wet solid. | |
| 2066. |
Azeotropism for ethyl alcohol-water system disappears by |
| A. | increasing temperature |
| B. | decreasing pressure |
| C. | increasing pressure |
| D. | no means |
| Answer» C. increasing pressure | |
| 2067. |
Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the |
| A. | mass transfer co-efficient. |
| B. | thermal diffusivity. |
| C. | kinematic viscosity. |
| D. | volumetric diffusivity. |
| Answer» B. thermal diffusivity. | |
| 2068. |
Degree of freedom for leaching and solvent extraction process is |
| A. | 1 |
| B. | 3 |
| C. | 0 |
| D. | 2 |
| Answer» C. 0 | |
| 2069. |
Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maxi-mum equilibrium moisture ? |
| A. | Anthracite coal |
| B. | Rag paper |
| C. | Bamboo |
| D. | Inorganic solids |
| Answer» D. Inorganic solids | |
| 2070. |
Separation of a mixture of two gases by absorption in the liquid solvent depends upon the difference in their |
| A. | viscosity |
| B. | density |
| C. | solubility |
| D. | relative volatility |
| Answer» D. relative volatility | |
| 2071. |
Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation. |
| A. | molecular |
| B. | extractive |
| C. | steam |
| D. | simple |
| Answer» E. | |
| 2072. |
Which of the following equipments is not used in liquid-liquid extraction ? |
| A. | Pachuka tank |
| B. | Agitated vessels |
| C. | Centrifugal extractors |
| D. | Packed towers |
| Answer» B. Agitated vessels | |
| 2073. |
Small dia distillation column can be a |
| A. | packed column |
| B. | sieve tray |
| C. | bubble cap |
| D. | any of these |
| Answer» B. sieve tray | |
| 2074. |
If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is |
| A. | 0 |
| B. | 1 |
| C. | < 1 |
| D. | > 1 |
| Answer» C. < 1 | |
| 2075. |
An air-water vapour mixture has a dry bulb temperature of 60 C and a dew point temperature of 40 C. The total pressure is 101.3 kPa and the vapour pressure of water at 40 C and 60 C are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is |
| A. | 0.048 |
| B. | 0.079 |
| C. | 0.122 |
| D. | 0.152 |
| Answer» E. | |
| 2076. |
__________ column is used in gas absorption process. |
| A. | Wetted wall |
| B. | Seive/perforated tray |
| C. | Bubble cap |
| D. | Packed |
| Answer» E. | |
| 2077. |
At what value of reflux ratio, number of theoretical plates in a distillation column is minimum ? |
| A. | 0 |
| B. | 1 |
| C. | |
| D. | < 1 |
| Answer» D. < 1 | |
| 2078. |
Batch tray dryers suffers from the disadvantage of |
| A. | high maintenance cost. |
| B. | non-uniform & low production rate. |
| C. | high labour cost & low heat economy. |
| D. | all 'a', 'b' & 'c'. |
| Answer» D. all 'a', 'b' & 'c'. | |
| 2079. |
In a moderately sized packed absorption tower, channeling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter |
| A. | > 4 :1 |
| B. | < 8 : 1 |
| C. | > 8:1 |
| D. | < 6:1 |
| Answer» D. < 6:1 | |
| 2080. |
Unsaturated air (with dry and wet bulb temperatures being 35 and 25 C respectively) is passed through water spray chamber maintained at 35 C. The air will be |
| A. | cooled |
| B. | humidified |
| C. | both (a) & (b) |
| D. | dehumidified |
| Answer» C. both (a) & (b) | |
| 2081. |
For absorbing a sparingly soluble gas in a liquid, the |
| A. | gas side co-efficient should be increased. |
| B. | liquid side coefficient should be increased. |
| C. | gas side co-efficient should be decreased. |
| D. | liquid side co-efficient should be decreased. |
| Answer» C. gas side co-efficient should be decreased. | |
| 2082. |
A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height. |
| A. | 10-15 |
| B. | 30-40 |
| C. | 70-80 |
| D. | 90-100 |
| Answer» B. 30-40 | |
| 2083. |
The boiling points of pure components of a binary system __________ with increase in total pressure of the system. |
| A. | decreases |
| B. | increases |
| C. | remains unchanged |
| D. | may increase or decrease, depends on the system. |
| Answer» C. remains unchanged | |
| 2084. |
The change in enthalpy, when a unit quantity of gas is absorbed by relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists) is termed as the |
| A. | differential heat of adsorption. |
| B. | heat of wetting. |
| C. | integral heat of adsorption. |
| D. | none of these. |
| Answer» B. heat of wetting. | |
| 2085. |
In a gas-liquid absorption coloumn, for obtaining the maximum absorption efficiency |
| A. | liquid stream should be distributed uniformly. |
| B. | gas stream should be distributed uniformly. |
| C. | both gas as well as liquid streams should be distributed uniformly. |
| D. | by passing should be completely avoided. |
| Answer» D. by passing should be completely avoided. | |
| 2086. |
Which of the following is a suitable absorbent for removal of H2S from natural gas ? |
| A. | Vetrocoke solution |
| B. | Monoethanol amine (MEA) |
| C. | Dilute |
| D. | Hot water |
| Answer» C. Dilute | |
| 2087. |
Reverse osmosis is also called |
| A. | dialysis |
| B. | electrodilysis |
| C. | diffusion |
| D. | ultrafiltration. |
| Answer» E. | |
| 2088. |
Which of the following is not a batch drier? |
| A. | Truck drier |
| B. | Agitated pan drier |
| C. | Fluidised bed drier |
| D. | Vacuum shelf drier |
| Answer» D. Vacuum shelf drier | |
| 2089. |
Steam distillation is not recommended to be used, if the |
| A. | azeotropic mixture is to be separated and the final product is miscible with water. |
| B. | liquids decompose, if distilled directly at atmospheric pressure. |
| C. | material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature. |
| D. | material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature. |
| Answer» B. liquids decompose, if distilled directly at atmospheric pressure. | |
| 2090. |
Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are |
| A. | 1 |
| B. | 8 |
| C. | 9 |
| D. | 10 |
| Answer» D. 10 | |
| 2091. |
Molecular diffusion is caused by the |
| A. | transfer of molecules from low concentration to high concentration region. |
| B. | thermal energy of the molecules. |
| C. | activation energy of the molecules. |
| D. | potential energy of the molecules. |
| Answer» C. activation energy of the molecules. | |
| 2092. |
Schimdt number and Lewis number for pure air at atmospheric conditions are respectively |
| A. | < 1 and 1 |
| B. | 1 and 0 |
| C. | >1 and 1 |
| D. | 0 and 1 |
| Answer» B. 1 and 0 | |
| 2093. |
Below is given an equilibrium moisture curve of a substance. State which regions represent free moisture and unbound moisture respectively. |
| A. | II, III |
| B. | II, IV |
| C. | IV, III |
| D. | IV, II |
| Answer» B. II, IV | |
| 2094. |
Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for |
| A. | constant molal overflow |
| B. | total reflux |
| C. | constant relative volatility |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 2095. |
In a binary system, separation is very efficient, when the relative volatility is |
| A. | 1 |
| B. | > 1 |
| C. | < 1 |
| D. | 0.5 |
| Answer» C. < 1 | |
| 2096. |
The binary diffusivity in gases does not depend upon the |
| A. | pressure |
| B. | temperature |
| C. | nature of the components |
| D. | none of these |
| Answer» E. | |
| 2097. |
1 kg of a saturated aqueous solution of a highly soluble component A at 60 C is cooled to 25 C. The solubility limits of A are (0.6 kgA/kg water) at 60 C and (0.2 kgA/kg water) at 25 C. The amount in kg of the crystals formed is |
| A. | 0.4 |
| B. | 0.25 |
| C. | 0.2 |
| D. | 0.175 |
| Answer» D. 0.175 | |
| 2098. |
The absorption factor is defined as (where, L = liquid flow rate, G = gas flow rate and, m = slope of the equilibrium line) |
| A. | <img src="/_files/images/chemical-engineering/mass-transfer/330-631-1.png"> |
| B. | <img src="/_files/images/chemical-engineering/mass-transfer/330-631-2.png"> |
| C. | <img src="/_files/images/chemical-engineering/mass-transfer/330-631-3.png"> |
| D. | <img src="/_files/images/chemical-engineering/mass-transfer/330-631-4.png"> |
| Answer» B. <img src="/_files/images/chemical-engineering/mass-transfer/330-631-2.png"> | |
| 2099. |
Smoke is an example of |
| A. | solid dispersed in liquid |
| B. | solid dispersed in gas |
| C. | liquid dispersed in gas |
| D. | gas dispersed in liquid |
| Answer» C. liquid dispersed in gas | |
| 2100. |
Which of the following adsorbant is used in the refinning of sugar ? |
| A. | Bone charcoal |
| B. | Wood charcoal |
| C. | Silica gel |
| D. | Activated clay |
| Answer» B. Wood charcoal | |