Q. Statement 1: Duhring’s rule states that the ratio of temperatures at which two solutions have the same vapor pressure is constant.
Statement 2: Duhring’s rule states that the boiling point of a solution is a linear function of the boiling point of pure water at the same pressure.

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Q. Statement 1: In a multiple effect evaporator, the overall temperature drop is equal to the individual drops at each step.
Statement 2: In a multiple effect evaporator, the total area is equal to the sum of the individual areas.

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Q. Statement 1: Forward feeding requires pumps for the feed at every step.
Statement 2: In a backward feeding arrangement, the most concentrated feed is exposed to the maximum steam in order to remove heat. This is its advantage.

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Q. One disadvantage with backward feeding is that the feed gets very concentrated at the beginning few units itself and hence it’s difficult to feed it to the next evaporator unit.

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Q. Mixed feed arrangement offers the advantage of omitting the usage of pumps by transferring feed in the direction of low pressure. That’s an advantage taken from forward feeding arrangement.

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Q. At a food processing industry, the steam was re-compressed and a small amount of steam at high pressures and temperatures was sent into the next evaporation chamber in a multiple effect evaporator. Which of the following is true with respect to the above sentences?

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Q. Statement 1: Horizontal tube evaporator is easy for cleaning.
Statement 2: Horizontal tube evaporator has a disadvantage of hindering agitation of the feed.

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Q. Statement 1: In a rising film evaporator, the feed can be very viscous.
Statement 2: In a rising film evaporator, the feed cannot be heat sensitive.

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Q. In a rising film evaporator, the temperature difference need not be as high as that in a falling film evaporator.

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Q. Plate evaporators are used in recovering aroma from fruit juices.

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Q. Statement 1: Scraped surface evaporators are used in the dairy industry.
Statement 2: Plate evaporators can be used for viscous liquids.

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Q. Industry A is low on budget and is used in the sugar industry. Industry B wants to invest in a good evaporator. They are needed for meat extracts. Which evaporators will you suggest for each of them?

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Q. A major reason as to why evaporators and their selection for different applications in the food industry is very important is because ______

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Q. Desolventization which is done in certain evaporators is more similar to distillation than evaporation.

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Q. In flashing of jams, the temperature of concentrated jam _____ on flashing. Also, the vapor pressure of the concentrated jam _____

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Q. In plate evaporator, the heat transfer coefficient is high in spite of low residence time because _____

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Q. Shifting of a pair of ripened apples from the store house to the vegetable cart is called mass transfer.

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Q. Statement 1: When alcohol is allowed to move from chamber A to chamber B when a barrier between them is removed, it is called multi phase diffusion.
Statement 2: When oxygen is made to diffuse into the water, it’s called continuous molecular diffusion.

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Q. Velocity gradient is the main driving force in mass transfer.

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Q. Statement 1: A phase boundary exists between alcohol and oxygen.
Statement 2: Phase boundary varies with agitation. It is inversely proportional to the amount of agitation provided.

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