Mass Transfer

471.The McCabe ΔL law states that the

1. Molar heats of vaporisation of components are nearly equal
2. Linear crystal growth rate depends on the degree of super-saturation
3. Linear crystal growth rate does not depend on the crystal size
4. Linear crystal growth rate depends on the crystal size

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472.The minimum liquid rate to be used in an absorber corresponds to an operating line

1. Of slope = 1
2. Of slope = 0.1
3. Tangential to the equilibrium curve
4. None of these

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473.The minimum number of theoretical plates is required for achieving a given separation in distillation column with

1. No reflux
2. Total reflux
3. Zero reflux ratio
4. Minimum reflux ratio

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474.The most common packing used in industrial operations is _________ rings.

1. Raschig
2. Lessing
3. Cross-partition
4. Single spiral

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475.The most economical range of absorption factor is

1. 0 to 0.5
2. 0 to 3
3. 1.25 to 2
4. 5 to 15

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476.The most efficient cooling tower out of the following is

1. Induced draft
2. Forced draft
3. Natural draft
4. Atmospheric

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477.The operating cost of a distillation column at minimum reflux ratio is

1. Minimum
2. Maximum
3. Infinite
4. Zero

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478.The operating line for an absorber is curved, when plotted in terms of

1. Mole fractions
2. Mole ratios
3. Partial pressure
4. Mass fractions

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479.The operation involved when the soluble material is largely on the surface of an insoluble solid and is merely washed off by the solvent is called

1. Decoction
2. Percolation
3. Elutriation or elution
4. None of these

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480.The overall mass transfer co-efficient for the absorption of SO₂ in air with dilute NaOH solution can be increased substantially by

1. Increasing the gas film co-efficient
2. Increasing the liquid film co-efficient
3. Increasing the total pressure
4. Decreasing the total pressure

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