MCQGeeks
0 : 0 : 1
CBSE
JEE
NTSE
NEET
English
UK Quiz
Quiz
Driving Test
Practice
Games
Quiz
Chemical Engineering
Mass Transfer
Quiz 10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Q.1
__________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower.
Sherwood
Stanton
Lewis
Peclet
Q.2
Pick out the wrong statement.
In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed
In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency
For Laminar flow over a plate of length L, the local mass transfer co-efficient at a distance L from the leading edge is 1.5 x 10⁻²m/s. Then the average mass transfer co-efficient for the plate is
The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity
Q.3
The term "cooling range" in a cooling tower refers to the difference in the temperature of
Cold water leaving the tower and the wet bulb temperature of the surrounding air
Hot water entering the tower and the wet bulb temperature of the surrounding air
Hot water entering the tower and the cooled water leaving the tower
None of these
Q.4
When both the fluids flow concurrently in an absorber, the slope of the operating line is
- ve
+ ve
1
-1
Q.5
Smoke is an example of
Solid dispersed in liquid
Solid dispersed in gas
Liquid dispersed in gas
Gas dispersed in liquid
Q.6
Solvent used in extractive distillation
Is of low volatility
Forms a low boiling azeotrope
Forms a high boiling azeotrope
Does not alter the relative volatility of the original components
Q.7
Solvent used in extractive distillation
Changes the relative volatility of the original components
Should be of high volatility
Should form azeotropes with the original components
All of the above
Q.8
High pressure at the bottom of a distillation tower handling heat sensitive materials results in
Thermal decomposition of bottoms
Increased relative volatility
Erosion of the tower
Very efficient operation
Q.9
In a counter-current extractor, as the axial mixing increases, the extraction efficiency
Increases
Decreases
Remains unchanged
Depends on the pressure of the system
Q.10
Pick out the wrong statement. Raoult's law does not apply, when the
Size of component molecules are not equal
Attractive forces between like and unlike molecules in the solution are approximately equal
Component molecules are nonpolar
Chemical combination or molecular association between unlike molecules takes place in the formation of solution
Q.11
__________ equation applies to diffusivities in liquids.
Gilliland
Hirschfelder
Wilke and Chang
None of these
Q.12
J
D
factor for mass transfer is a function of Reynolds number. Mass transfer by molecular diffusion from a single drop to surrounding still air is given by
N
sh
= 2
N
st
= 2
N
sc
= 2
None of these
Q.13
The minimum liquid rate to be used in an absorber corresponds to an operating line
Of slope = 1
Ofslope = 0.1
Tangential to the equilibrium curve
None of these
Q.14
Which of the following is an undesirable property for an absorbing solvent?
Low vapour pressure
Low velocity
Low freezing point
None of these
Q.15
__________ column is used in gas absorption process.
Wetted wall
Seive/perforated tray
Bubble cap
Packed
Q.16
Penetration theory states that the mass transfer co-coefficient is equal to (where, D
e
is diffusivity and 't' is time)
(D
e
.t)
1/2
(D
e
/t)
1/2
(4D
e
/πt)
1/2
(4D
e
/t)
Q.17
In paper industry, paper is dried in a __________ dryer.
Tunnel
Heated cylinder
Conveyor
Festoon
Q.18
Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer.
Rotary
Vacuum
Tunnel
Tray
Q.19
Mass transfer co-efficient of liquid is
Affected more by temperature than that for gases
Affected much less by temperature than that for gases
Not affected by the temperature
None of these
Q.20
The rate of mass transfer is not dependent upon the
Degree of dispersion of one fluid in the other
Interfacial surface exposed between the phases
Both A & B
None of these
Q.21
Pick out the wrong statement:
In case of an absorber, the operating line is always above the equilibrium curve
Absorption factor is constant, when the equilibrium and operating lines are straight
In case of a stripper, the equilibrium curve is always below the operating line
In the absorption of low solubility gases, the liquid film is the controlling resistance
Q.22
What is the degree of freedom of an absorption process in which only one component is transferred between phases?
3
2
4
1
Q.23
In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in
Reducing the axial mixing
Increasing the rate of extraction
Maintaining the concentration difference between the two phases
All of the above
Q.24
Pick out the wrong statement:
Change in barometric pressure does not affect the relative humidity
In case of a packed tower, the operating velocity is about half of the flooding velocity, generally
'Elution' means the desorption of the adsorbed solute by a solvent
The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity
Q.25
On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in
Greater degree of separation with a fixed number of trays
Increased reboiler load
Increased reflux ratio
None of these
Q.26
As per Gilliland's equation, the diffusivity is
Directly proportional to 'T
1.5
'
Inversely proportional to 'P'
Dependent on the molecular volume & molecular weight of components
All of the above
Q.27
H₂S present in naphtha reformed gas is removed by absorbing with
Ethanolamine
K₂CO₃
HCl
Vacuum gas oil
Q.28
Corresponding to Nusselt number in heat transfer, the dimensionless group in mass transfer is the __________ number.
Sherwood
Schmidt
Peclet
Stanton
Q.29
Separation of a mixture of two gases by absorption in the liquid solvent depends upon the difference in their
Viscosity
Density
Solubility
Relative volatility
Q.30
Steam distillation is not recommended to be used, if the
Azeotropic mixture is to be separated and the final product is miscible with water
Liquids decompose, if distilled directly at atmospheric pressure
Material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature
Material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature
Q.31
Chemisorption compared to physical absorption has
Lower adsorption rate
Lower capacity of the solvent for the solute gas
Increased utilisation of stagnant zones of the liquid phase
None of these
Q.32
What is the reflux ratio at total reflux?
Zero
Infinity
Unity
Data insufficient
Q.33
The diffusivity (D) in a binary gas mixture is related to the pressure (P) as
D ∝ P
0.5
D ∝ 1/P
0.5
D ∝ 1/P
D ∝ 1/P
1.5
Q.34
In distillation columns, the number of bubble caps per tray primarily depends upon the
Allowable liquid velocity
Allowable gas velocity
Allowable gas and liquid velocities
Feed composition
Q.35
Gaseous diffusivity at atmospheric pressure is of the order of __________ cm²/second.
1
1 to 5
5 to 10
> 10
Q.36
For gas absorption, low viscosity solvents are preferred, because of their
Better flow characteristics
Low pumping pressure drop
Rapid absorption rates
All of the above
Q.37
Mass transfer co-efficient 'K' according to penetration theory varies with mass dif-fusivity as
D
0.5
D
1/D
D
1.5
Q.38
For absorbing a sparingly soluble gas in a liquid
Gas side mass transfer co-efficient should be increased
Liquid side mass transfer co-efficient should be increased
Liquid side mass transfer co-efficient should be decreased
Mass transfer co-efficient must be kept constant
Q.39
Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content.
Rotary
Tray
Freeze
None of these
Q.40
In an absorber, HETP does not vary with the
Flow rate of gas
Flow rate of liquid
Type and size of packing
None of these
Q.41
Use of natural draft cooling tower is practised, when the air has low
Humidity
Temperature
Both A & B
Neither A nor B
Q.42
Raoult's law applies to the
All liquid solutions
Non-ideal solution only
Non-volatile solute
Solvents
Q.43
At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent.
100
0
50
Between 0 and 100
Q.44
Which of the following same diameter columns gives lowest pressure drop per unit height?
Bubble-cap column
Sieve-plate column
Packed column (stacked)
Randomly packed column
Q.45
Reverse osmosis is also called
Dialysis
Electrodilysis
Diffusion
Ultrafiltration
Q.46
Heat sensitive materials like certain pharmaceuticals and food stuffs can be dried in a/an __________ dryer.
Indirect tray
Spray
Freeze
None of these
Q.47
According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity)
D
D
2
D
0.5
1/D
Q.48
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
Differential heat of adsorption
Heat of wetting
Integral heat of adsorption
None of these
Q.49
The equipment used in the extraction of highly corrosive radio active liquids is
Pulse column
Spray column
Mixer settler
Baffle tower
Q.50
The value of N
A
/(N
A
+ N
B
) for steady state molecular diffusion of gas 'A' through non-diffusing gas 'B' is
1
∞
0.5
2
0 h : 0 m : 1 s
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Support mcqgeeks.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page