Mass Transfer

221.If the specific heats of a gas and a vapor are 0.2KJ/Kg.°K and 1.5 KJ/Kg.°K respectively, and the humidity is 0.01; the humid heat in KJ/°Kg. is

1. 0.31
2. 0.107
3. 0.017
4. 0.215

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222.If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively

1. [x_D/(R_D + 1)], [RD/(R_D + 1)]
2. [R_D/(R_D + 1)], [xD/(x_D + 1)]
3. [x_D/(R_D + 1)], [(RD + 1)/R_D]
4. None of these

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223.In a binary distillation column, if the feed contains 40 mole % vapour, the q line will have a slope of

1. 1.5
2. -0.6
3. -1.5
4. 0.6

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224.In a binary system, separation is very efficient, when the relative volatility is

1. 1
2. > 1
3. < 1
4. 0.5

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225.In a counter-current extractor, as the axial mixing increases, the extraction efficiency

1. Increases
2. Decreases
3. Remains unchanged
4. Depends on the pressure of the system

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226.In a counter-current liquid extractor

1. Both liquids flow at fixed rate
2. Both liquids can have any desired flow rate
3. Only one of the liquids may be pumped at any desired rate
4. Liquid's flow rate depends upon the temperature and pressure

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227.In a distillation column, with increase in the reflux ratio, the heat removed in the cooler

1. Increases
2. Decreases
3. Remains unaffected
4. And the heat required in reboiler decreases

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228.In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads?
Reflux conditions:
(i) Reflux stream is completely liquid and is at its bubble point.
(ii) Reflux stream is below its bubble point.

1. Condenser and reboiler loads are the same in both the cases
2. Reboiler load is the same in both the cases but condenser load is higher in case (ii)
3. Condenser load is the same in both the cases but reboiler load is higher in case (ii)
4. Both condenser and reboiler loads are higher in case (ii) as compared to case (i)

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229.In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the

1. Range is 15°F
2. Approach is 10°F
3. Both (A) & (B)
4. Neither (A) nor (B)

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230.In a gas-liquid absorption column, for obtaining the maximum absorption efficiency

1. Liquid stream should be distributed uniformly
2. Gas stream should be distributed uniformly
3. Both gas as well as liquid streams should be distributed uniformly
4. By passing should be completely avoided

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