For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a __________ evaporator. (A) High pressure (B) Vacuum (C) Backward feed (D) None of these

For concentrating an aqueous solution of a material like anhydrous

Na2SO4, whose solubility decreases with rise in temperature, the most

suitable evaporator is a __________ evaporator.

(A) High pressure

(B) Vacuum

(C) Backward feed

(D) None of these

by

1 Answer

Answer :

(B) Vacuum

by

Related questions

A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides (A) Higher economy (B) Lower capacity (C) Both (A) & (B) (D) Lower economy

Description : A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides (A) Higher economy (B) Lower capacity (C) Both (A) & (B) (D) Lower economy

Last Answer : (A) Higher economy

Which of the following is the most suitable material of construction for evaporator & its tubes for concentrating NaOH solution to 70%? (A) Cast iron (B) Steel (C) Nickel (D) Karbate

Description : Which of the following is the most suitable material of construction for evaporator & its tubes for concentrating NaOH solution to 70%? (A) Cast iron (B) Steel (C) Nickel (D) Karbate

Last Answer : (C) Nickel

. An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is (A) 4000 (B) 9000 (C) 4600 (D) 3000

Description : . An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is (A) 4000 (B) 9000 (C) 4600 (D) 3000

Last Answer : (A) 4000

Pick out the wrong statement. (A) At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature (B) Normally, the gases which are easily liquefied are more soluble in common solvents (C) The gases which are capable of forming ions in aqueous solution are much more soluble in water than in other solvents (D) At constant pressure, solubility of a gas in a liquid increases with rise in temperature

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Last Answer : (A) At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature

. A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of all the effects is -less than that in a single effect evaporator system (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect (C) Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system (D) Heat transfer co-efficient in a single effect is much lower than that in any effect in a multi-effect system

Description : . A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of ... in a single effect is much lower than that in any effect in a multi-effect system

Last Answer : (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect

Agitated film evaporator is suitable for concentrating __________ liquids. (A) Foaming (B) Viscous (C) Very thin (D) Corrosive

Description : Agitated film evaporator is suitable for concentrating __________ liquids. (A) Foaming (B) Viscous (C) Very thin (D) Corrosive

Last Answer : (B) Viscous

Nickel made/clad equipments are suitable for handling (A) Ammonia (both aqueous & anhydrous) (B) Fruit juices, milk & its products and caustic soda solution (C) Nitric acid & hydrochloric acid (concentrated) (D) Sulphuric acid (concentrated)

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Last Answer : (B) Fruit juices, milk & its products and caustic soda solution

. In a backward feed multiple effect evaporator (A) Feed is introduced in the first effect (B) Feed flows from low pressure to high pressure (C) No pumps are required between successive effects (D) None of these

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Last Answer : (B) Feed flows from low pressure to high pressure

Pick out the wrong statement. (A) The value of hydrostatic head increases with increase in vacuum in the effect in a multiple effect evaporator system (B) Entering velocity of the liquid in the tubes of natural circulation evaporators is in the range of 0.3 to 0.9 metre/second (C) Duhring's plot is used for calculating the concentration of solution (D) In a multiple effect evaporation system, the number of effects is limited by the total boiling point rise

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Last Answer : (C) Duhring's plot is used for calculating the concentration of solution

The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the (A) Solution has an elevation of boiling point (B) Evaporators operate under vacuum (C) Evaporators operate at atmospheric pressure (D) None of these

Description : The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the (A) Solution has ... B) Evaporators operate under vacuum (C) Evaporators operate at atmospheric pressure (D) None of these

Last Answer : (A) Solution has an elevation of boiling point

In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease, depends on the vacuum

Description : In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease, depends on the vacuum

Last Answer : (A) Increases

The suitable evaporator for concentration of foaming liquids is a __________ evaporator. (A) Long tube (B) Short tube (C) Vacuum (D) Falling film

Description : The suitable evaporator for concentration of foaming liquids is a __________ evaporator. (A) Long tube (B) Short tube (C) Vacuum (D) Falling film

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If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as (A) Solubility increases as temperature increases (B) Solubility increases as temperature decreases (C) Solubility is independent of temperature (D) Solubility increases or decreases with temperature depending on the Gibbs free energy change of solution

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Last Answer : (B) Solubility increases as temperature decreases

For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is (A) Forward (B) Backward (C) Parallel (D) None of these

Description : For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is (A) Forward (B) Backward (C) Parallel (D) None of these

Last Answer : (B) Backward

The purpose of providing bleed points in the evaporator is to (A) Admit the feed (B) Remove the product (C) Facilitate removal of non-condensable gases (D) Create vacuum

Description : The purpose of providing bleed points in the evaporator is to (A) Admit the feed (B) Remove the product (C) Facilitate removal of non-condensable gases (D) Create vacuum

Last Answer : (C) Facilitate removal of non-condensable gases

Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward feeding in multiple effect evaporation (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product

Description : Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward ... (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product

Last Answer : (A) Get economical temperature difference by using moderate pressure steam

Which of the following is NOT a general property of hydroxide bases in aqueous solution? w) High solubility x) Bitter taste y) Ability to neutralize aqueous acid solutions z) Ability to change phenolphthalein from colorless to red

Description : Which of the following is NOT a general property of hydroxide bases in aqueous solution? w) High solubility x) Bitter taste y) Ability to neutralize aqueous acid solutions z) Ability to change phenolphthalein from colorless to red

Last Answer : ANSWER: W -- HIGH SOLUBILITY (The hydroxides of the alkali metals are soluble in water but all the other metal hydroxides are only moderately or sparingly soluble.)

1 kg of a saturated aqueous solution of a highly soluble component A at 60°C is cooled to 25°C. The solubility limits of A are (0.6 kgA/kg water) at 60°C and (0.2 kgA/kg water) at 25°C. The amount in kg of the crystals formed is: (A) 0.4 (B) 0.25 (C) 0.2 (D) 0.175

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Last Answer : (C) 0.2

Evaporator used for concentrating tomato juice is made of (A) Nickel (B) Brass (C) Stainless steel-glass lined (D) Cast iron-rubber lined

Description : Evaporator used for concentrating tomato juice is made of (A) Nickel (B) Brass (C) Stainless steel-glass lined (D) Cast iron-rubber lined

Last Answer : (C) Stainless steel-glass lined

A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is (A) 6000 (B) 24000 (C) 60000 (D) 48000

Description : A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is (A) 6000 (B) 24000 (C) 60000 (D) 48000

Last Answer : (B) 24000

In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate

Description : In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate

Last Answer : (C) Foaming of the solution

In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient (A) Increases (B) Decreases (C) Is not affected (D) May increase or decrease; depends on the feed

Description : In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient (A) Increases (B) Decreases (C) Is not affected (D) May increase or decrease; depends on the feed

Last Answer : (B) Decreases

The advantage of backward feed multiple effect evaporators over forward feed units is that (A) Heat sensitive material can be handled (B) There is no additional cost of pumping (C) Most concentrated liquid is at highest temperature (D) Equal heat transfer co-efficients exist in various effects

Description : The advantage of backward feed multiple effect evaporators over forward feed units is that (A) Heat sensitive material can be handled (B) There is no additional cost of pumping ... liquid is at highest temperature (D) Equal heat transfer co-efficients exist in various effects

Last Answer : (C) Most concentrated liquid is at highest temperature

Define the following : Solute , Solvent , Solution , Aqueous Solution & Solubility.

Description : Define the following : Solute , Solvent , Solution , Aqueous Solution & Solubility.

Last Answer : Ans : Solute : The component of the solution present in smaller amount is called solute. It is also defined as the substance that gets dissolved in the solvent. Example : Glucose is solute in glucose solution. ... grams / 100 grams. Solubility of sugar in water at 100 degree C is 487 grams/100 ml.

Pick out the wrong statement regarding the solubility characteristics of high polymers. (A) Greater the degree of cross-linking in the polymer, lesser is its solubility (B) Polymers having more aliphatic character are more soluble in aliphatic solvents, while those polymers having more aromatic character are more soluble in aromatic solvents (C) Swelling tendency or solubility of polymers in a particular solvent decreases with increase in molecular weight of the solvent (D) High molecular weight polymers on dissolving gives solution of very low viscosity

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Last Answer : (D) High molecular weight polymers on dissolving gives solution of very low viscosity

Economy of an evaporator is influenced by the (A) Steam pressure (B) Feed temperature (C) Number of effect (D) Both (B) & (C)

Description : Economy of an evaporator is influenced by the (A) Steam pressure (B) Feed temperature (C) Number of effect (D) Both (B) & (C)

Last Answer : (D) Both (B) & (C)

The actual temperature drop across the heating surface in an evaporator depends on the (A) Feed (B) Depth of liquid over heating surface (C) Pressure difference between steam chest and vapour space (D) All (A), (B) and (C)

Description : The actual temperature drop across the heating surface in an evaporator depends on the (A) Feed (B) Depth of liquid over heating surface (C) Pressure difference between steam chest and vapour space (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

Description : Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

Last Answer : (A) Vacuum

Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

Description : Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

Last Answer : (A) Vacuum

A negative heat of solution indicates that: w) an endothermic dissolving process occurs x) solute solubility increases with rising solution temperature y) solute solubility decreases with rising solution temperature z) super-saturation conditions exist

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Last Answer : ANSWER: Y -- SOLUTE SOLUBILITY DECREASES WITH RISING SOLUTION TEMPERATURE

Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)

Description : Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)

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It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is (A) 3.06 × 10 5 (B) 6.12 × 10 5 (C) 7.24 × 10 5 (D) 9.08 × 10

Description : It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of ... 3.06 10 5 (B) 6.12 10 5 (C) 7.24 10 5 (D) 9.08 10

Last Answer : (A) 3.06 × 10

Fruit juice (a heat sensitive material) can be concentrated in a __________ evaporator. (A) Long tube (B) Falling film (C) High pressure (D) None of these

Description : Fruit juice (a heat sensitive material) can be concentrated in a __________ evaporator. (A) Long tube (B) Falling film (C) High pressure (D) None of these

Last Answer : (B) Falling film

With increase in temperature, the solubility of gases in liquids, at fixed pressure (A) Increases (B) Decreases (C) Remain same (D) Either (A) or (B), depends on the system

Description : With increase in temperature, the solubility of gases in liquids, at fixed pressure (A) Increases (B) Decreases (C) Remain same (D) Either (A) or (B), depends on the system

Last Answer : (B) Decreases

Proteins are soluble in (A) Anhydrous acetone(B) Aqueous alcohol (C) Anhydrous alcohol (D) Benzene

Description : Proteins are soluble in (A) Anhydrous acetone(B) Aqueous alcohol (C) Anhydrous alcohol (D) Benzene

Last Answer : Answer : B

Explain why anhydrous HCl is a bad conductor electricity while aqueous HCl is a good conductor of electricity.

Description : Explain why anhydrous HCl is a bad conductor electricity while aqueous HCl is a good conductor of electricity.

Last Answer : Ans: Hcl is a covalent compound and has no ion but when dissolve into solution it under go dissociation and produce ions in the solution and hence conduct electricity.

Which is the most suitable for the concert-ration of highly concentrated solution? (A) Open pan evaporation (B) Long tube vertical evaporator (C) Agitated film evaporator (D) None of these

Description : Which is the most suitable for the concert-ration of highly concentrated solution? (A) Open pan evaporation (B) Long tube vertical evaporator (C) Agitated film evaporator (D) None of these

Last Answer : (A) Open pan evaporation

Vetrocoke solution is (A) A mixture of K2CO3 and As2O3 (B) K2SO4 (C) A mixture of Na2CO3 and As2O3 (D) Na2SO4

Description : Vetrocoke solution is (A) A mixture of K2CO3 and As2O3 (B) K2SO4 (C) A mixture of Na2CO3 and As2O3 (D) Na2SO4

Last Answer : (A) A mixture of K2CO3 and As2O3

Henry's law is closely obeyed by a gas, when its __________ is extremely high. (A) Pressure (B) Solubility (C) Temperature (D) None of these

Description : Henry's law is closely obeyed by a gas, when its __________ is extremely high. (A) Pressure (B) Solubility (C) Temperature (D) None of these

Last Answer : (D) None of these

The actual temperature drop across the heating surface of an evaporator depends on the (A) Liquid depth over the heating surface (B) Solution being evaporated (C) Pressure difference between the steam chest and the vapor space above the boiling liquid (D) All (A), (B) and (C)

Description : The actual temperature drop across the heating surface of an evaporator depends on the (A) Liquid depth over the heating surface (B) Solution being evaporated (C) Pressure difference between the steam chest and the vapor space above the boiling liquid (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

In a forward feed multiple effect evaporator, the pressure is (A) Highest in last effect (B) Lowest in last effect (C) Same in all effects (D) Dependent on the number of effects

Description : In a forward feed multiple effect evaporator, the pressure is (A) Highest in last effect (B) Lowest in last effect (C) Same in all effects (D) Dependent on the number of effects

Last Answer : (B) Lowest in last effect

Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Description : Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Last Answer : (3) higher temperature is attained for cooking Explanation: In pressure cooker boiling point of water increases due to high pressure.

Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Description : Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Last Answer : higher temperature is attained for cooking 

Fqra cold viscous feed, backward feed gives __________ than forward feed. (A) A higher capacity (B) A lower capacity (C) Lower economy (D) None of these

Description : Fqra cold viscous feed, backward feed gives __________ than forward feed. (A) A higher capacity (B) A lower capacity (C) Lower economy (D) None of these

Last Answer : (A) A higher capacity

For hot feed, forward feeding as compared to backward feeding results in __________ economy. (A) Increased (B) Decreased (C) No effect on (D) None of these

Description : For hot feed, forward feeding as compared to backward feeding results in __________ economy. (A) Increased (B) Decreased (C) No effect on (D) None of these

Last Answer : (A) Increased

Economy of a multiple effect evaporator is not influenced much by the (A) Boiling point elevations (B) Temperature of the feed (C) Rate of heat transfer (D) Ratio of the weight of the thin liquor to thick liquor

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Last Answer : (A) Boiling point elevations

Viscosity of a polymer solution or melt (A) Decreases with increase in molecular weight (B) Decreases with increase in temperature (C) Increases with increase in temperature (D) Does not vary with temperature rise

Description : Viscosity of a polymer solution or melt (A) Decreases with increase in molecular weight (B) Decreases with increase in temperature (C) Increases with increase in temperature (D) Does not vary with temperature rise

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Mild steel storage vessels are suitable for the storage of (A) Anhydrous ammonia (B) Fatty acids (C) Hydrochloric acid (95%) (D) Sulphuric acid (25%)

Description : Mild steel storage vessels are suitable for the storage of (A) Anhydrous ammonia (B) Fatty acids (C) Hydrochloric acid (95%) (D) Sulphuric acid (25%)

Last Answer : (A) Anhydrous ammonia

Pick out the wrong statement. (A) In a first order reaction, A → products; the reaction becomes slower as it proceeds, because the concentration of A decreases and the rate is proportional to the concentration of A (B) Transition state theory approaches the problem of calculating reaction rates by concentrating on the idea of activated complexes (C) According to the penetration theory, the mass transfer co-efficient decreases, if the exposure time of an eddy to the solute decreases (D) If the rate of an irreversible reaction, A + B → 2C is k.CA .CB , then the reaction is always elementary

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With increase in temperature, the mutual solubility of two liquids (A) Increases (B) Decreases (C) Remains unchanged (D) Decreases exponentially

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