Mass Transfer

91.Can a cooling tower cool water below the wet bulb temperature of inlet air?

1. Yes
2. No
3. Yes; but height of cooling tower will be prohibitively high
4. Yes; but the air flow rate should be excessively high

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92.Can the efficiency of a plate in the distillation tower be greater than 100%?

1. Yes
2. Normally not; but is possible if infinite number of plates are put
3. Never
4. Yes; if the reflux ratio is maximum

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93.Capacity of a rotary dryer depends on its

1. rpm
2. Inclination with ground surface
3. Both (A) and (B)
4. Neither (A) nor (B)

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94.Channelling in a packed tower results from the

1. High pressure drop
2. Maldistribution of liquid
3. Non-uniformity of packing
4. Both (B) and (C)

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95.Channelling is most severe

1. In towers packed with stacked packing
2. In towers packed randomly with crushed solids
3. In dumped packing of regular units
4. At very high liquid flow rate

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96.Chemisorption (chemical adsorption) is

1. Same as "Van der Waals" adsorption
2. Characterised by adsorption of heat
3. An irreversible phenomenon
4. A reversible phenomenon

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97.CO2 can be absorbed by

1. Hot cupric oxide
2. Heated charcoal
3. Cold Ca(OH)2
4. Alumina

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98.Co-current absorbers are usually used when the gas to be dissolved in the liquid is

1. Sparingly soluble
2. Highly soluble
3. A pure substance
4. A mixture

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99.Coffee is prepared from coffee beans by leaching with

1. Cold water
2. Hot water
3. Dilute hot caustic solution
4. Naphtha

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100.Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if

1. Mass transfer is accompanied by reaction
2. Diffusion of A is in stagnant medium B
3. Molecular mean free path is high
4. There is equimolar counter diffusion

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