Mass Transfer

341.One mole feed of a binary mixture of a given composition is flash vaporised at a fixed P and T. If Raoult's law is obeyed, then changing the feed composition would effect

1. The product composition but not the fraction vaporised
2. The product composition as well as the fraction vaporised
3. The fraction vaporised but not the product composition
4. Neither the product composition nor the fraction vaporised

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342.Only small amount of evaporation of water produces large cooling effects because of its

1. Large latent heat
2. Low viscosity
3. Small latent heat
4. None of these

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343.Operating velocity in a packed tower is usually _________ the flooding velocity.

1. Half
2. Twice
3. Equal to
4. More than

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344.Ordinary diffusion process is also called _________ diffusion.

1. Pressure
2. Thermal
3. Concentration
4. Forced

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345.Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in _________ tower.

1. Wetted wall
2. Bubble cap
3. Perforated tray
4. Packed

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346.Out of two equilibrium curves, first one lies above the diagonal and the second lies below the diagonal in the x-y plot. It means that separation by distillation is

1. Not possible in the second case unless vacuum is applied
2. Not possible in the second case unless high pressure is applied
3. More readily done in the second case compared to first one
4. None of these

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347.Overall efficiency of the distillation column is

1. The ratio of number of ideal plates to actual plates
2. The ratio of number of actual plates to ideal plates
3. Same as the Murphree efficiency
4. Always more than the point efficiency

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348.Packed column distillation is limited to the column _________ metres.

1. Height < 6
2. Diameter < 0.6
3. Both (A) & (B)
4. Neither (A) nor (B)

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349.Paper industry employs _________ driers.

1. Cylinder
2. Rotary
3. Spray
4. Fluidised bed

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350.Penetration model (theory) for mass transfer was enunciated by

1. Danckwerts
2. Toor and Marcello
3. Higbie
4. Kissinevskii

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