36 + Interview Questions in Azeotropic And Extractive Distillation in Distillation Design Page 1 InterviewSolution

1.	The locus of compositions that cannot be crossed by the given distillation process, is called?(a) Distillation line(b) Distillation Boundary(c) Distillation Map(d) Distillation regionThis question was addressed to me in an interview for job.My doubt stems from Extractive Distillation Terminology topic in section Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct answer is (b) Distillation Boundary Best explanation: The LOCUS of COMPOSITIONS that cannot be crossed by the GIVEN distillation PROCESS, the existence and LOCATION of such boundaries depend critically on the type of distillation in question.

Discussion

2.	Positive deviation from Raoult’s law results in?(a) Minimum boiling azeotrope(b) Maximum boiling azeotrope(c) Tangential azeotrope(d) Elliptical azeotropeThe question was posed to me in an internship interview.My question is from Azeotropic Elements in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» CORRECT ANSWER is (a) Minimum boiling azeotrope Easy explanation: The attraction between IDENTICAL molecules (A-A and B-B) is stronger than between different molecules (A-B), This may cause the formation of a minimum-boiling azeotrope and HETEROGENEITY.

Discussion

3.	Liquid reflux (L1), is used to control?(a) 1/E split(b) 1/2E split(c) 1/5E split(d) E splitI have been asked this question in quiz.I want to ask this question from Extractive Distillation Terminology in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct answer is (a) 1/E SPLIT Best explanation: LIQUID reflux (L1) is used to CONTROL the 1/E split in the rectifying section for the extractive middle VESSEL batch distillation column.

Discussion

4.	Ethanol is dehydrogenated oxidatively to acetaldehyde using a _____ Catalyst.(a) Ag(b) Pt(c) Pb(d) HgI had been asked this question at a job interview.I'm obligated to ask this question of Azeotropic Distillation topic in division Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct answer is (a) Ag For explanation: In ACETALDEHYDE oxidation, ETHANOL is dehydrogenated oxidatively to acetaldehyde USING a silver, brass or bronze catalyst.

Discussion

5.	Liquid flow out of middle vessel (LM) is used to control?(a) 2/E(b) 7/E(c) 8/E(d) 1/EThis question was posed to me during a job interview.My question is taken from Extractive Distillation Terminology topic in section Azeotropic and Extractive Distillation of Distillation Design
Answer» Right option is (a) 2/E To explain I would say: LIQUID FLOW out of MIDDLE vessel (LM) is used to control the 2/E split in the stripping section, for the EXTRACTIVE middle vessel batch DISTILLATION column.

Discussion

6.	Separating a maximum-boiling azeotrope using a light entrainer, this process is referred to as?(a) Re-extractive distillation(b) De-extractive distillation(c) Extractive distillation(d) Boil up distillationI got this question by my school teacher while I was bunking the class.Question is taken from Extractive Distillation topic in division Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct ANSWER is (a) Re-EXTRACTIVE distillation For explanation I would SAY: The same extractive distillation scheme can in principle be APPLIED to the symmetrical SYSTEM of separating a maximum-boiling azeotrope using a light entrainer and this process is referred to as re-extractive distillation.

Discussion

7.	A greater entrainer flowrate generally, yields better(a) Reflux(b) Boil up(c) Hold up(d) SeparationThe question was asked in quiz.This is a very interesting question from Extractive Distillation topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» The CORRECT option is (d) Separation Easy explanation: A greater ENTRAINER FLOWRATE generally yields better separation, but this increases the ENERGY demand in both columns and increases the reboiler temperature in the extractive COLUMN.

Discussion

8.	Heteroazeotropic (VLLE) distillation, often referred to as?(a) Azeotropic distillation(b) Exractive distilllaton(c) Batch Ditilation(d) Continous DistillationI got this question by my school teacher while I was bunking the class.My doubt is from Extractive Distillation in portion Azeotropic and Extractive Distillation of Distillation Design
Answer»

Discussion

9.	A minimum-boiling azeotrope can be formed by?(a) Azeotrope entrainer(b) Any chemical(c) Water(d) BenzeneThis question was posed to me in quiz.Origin of the question is Azeotropic Distillation in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Right answer is (a) Azeotrope entrainer The explanation: A minimum-boiling azeotrope can be formed by an azeotrope-forming entrainer to an existing azeotropic MIXTURE or close-boiling mixture for which separation by CONVENTIONAL DISTILLATION is not feasible.

Discussion

10.	The most commonly used membrane technology for liquid azeotropic mixtures is?(a) Pervaporation(b) Evaporation(c) De-evaporation(d) CondensationI have been asked this question by my college professor while I was bunking the class.I need to ask this question from Azeotropic Elements topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct CHOICE is (a) PERVAPORATION To explain I would say: The most commonly USED membrane technology for liquid azeotropic mixtures is pervaporation with low PRESSURE on the permeate SIDE of the membrane so as to evaporate the permeate.

Discussion

11.	Acetone and methanol form a binary minimum-boiling azeotrope, of about?(a) 75.8% acetone(b) 80% acetone(c) 70% acetone(d) 50% acetoneI had been asked this question in unit test.My question is taken from Extractive Distillation Terminology in division Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct answer is (a) 75.8% acetone Explanation: Acetone and methanol FORM a binary minimum-boiling azeotrope of about 78.5 MOLE % acetone, Water is MISCIBLE and zeotropic in the WHOLE COMPOSITION space.

Discussion

12.	The residue curves of an n component homogenous mixture is defined by?(a) n-1 ODE(b) n-2 ODE(c) n-3 ODE(d) n ODEThis question was posed to me in final exam.Query is from Extractive Distillation in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» RIGHT answer is (a) N-1 ODE The best I can explain: The residue curves of an n component HOMOGENOUS mixture is defined by n-1 ODE’s, where dxi/dE and E is DIMENSIONLESS warped TIME.

Discussion

13.	At constant pressure, there exhibits a nearly extreme point at zero concentration for one or several of the components this point is called?(a) Tangent pitch(b) Elliptical pitch(c) Parabolic pitch(d) Circular pitchThe question was asked during an interview.Origin of the question is Azeotropic Elements topic in section Azeotropic and Extractive Distillation of Distillation Design
Answer» Right option is (a) Tangent pitch To elaborate: This PHENOMENON is also called a tangent pinch, such MIXTURES are of great PRACTICAL importance, examples of COMMON tangentially zeotropic mixtures are acetone and WATER.

Discussion

14.	Which of the following equations are satisfied at azeotropic conditions?(a) A^v(v) + A^l(v) = 0(b) A^v(v) – A^l(v) = 0(c) A^v(v). A^l(v) = 0(d) A^v(v) =A^l(v)The question was posed to me during a job interview.The query is from Extractive Distillation in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct ANSWER is (b) A^v(v) – A^l(v) = 0 For EXPLANATION: A^v(v) and A^l(v) are the Helmholtz energy of the vapor and LIQUID PHASES respectively, V, V^0 and V^l are the total molar volume.

Discussion

15.	Young performed his azeotropic dehydration of alcohol by?(a) Continuous Method(b) Batch Method(c) Stage Method(d) Full MethodI got this question in final exam.I want to ask this question from Azeotropic Distillation in section Azeotropic and Extractive Distillation of Distillation Design
Answer» RIGHT answer is (b) Batch Method Explanation: YOUNG, who demonstrated the first industrial application, azeotropic distillation is still used today in the PRODUCTION and DEHYDRATION of alcohol.

Discussion

16.	Heterogeneous azeotropes exist when the vapor is in equilibrium with?(a) Dual liquid phase(b) Dual Solid phase(c) Dual Phase(d) Triple PhaseThe question was posed to me by my college director while I was bunking the class.The question is from Azeotropic Distillation topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» RIGHT answer is (c) Dual Phase Easy explanation: Heterogeneous azeotropes exist when the vapor is in equilibrium with TWO liquid PHASES. Heterogeneous AZEOTROPIC distillation is widely USED for the separation of azeotropes.

Discussion

17.	Bottom flowrate (B) is used to control the level in?(a) Rampage(b) Reflux(c) Reboiler(d) Condenser drumI have been asked this question in my homework.Asked question is from Extractive Distillation Terminology topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» The CORRECT choice is (c) Reboiler Explanation: Bottom flowrate (B) is used to CONTROL the level in reboiler, for the extractive middle VESSEL batch DISTILLATION column.

Discussion

18.	When y = E(x), where E is?(a) Mapping function(b) Entity function(c) Frequency function(d) Phase functionI had been asked this question in an internship interview.My question is from Extractive Distillation in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct OPTION is (a) MAPPING function Explanation: E is the EQUILIBRIUM mapping function that ASSIGNS a composition in the liquid phase to the CORRESPONDING equilibrium vapor phase composition, and Tbp and Tdp are the mixture boiling temperature.

Discussion

19.	For easy separation, the relative volatility αi,j tends to?(a) 0(b) 1(c) 1.5(d) 0.5This question was posed to me in an international level competition.This interesting question is from Azeotropic Elements topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct option is (B) 1 Explanation: The SEPARATION at the azeotropic point is not POSSIBLE, because of the reason that the relative volatility αi,j is equal to ONE.

Discussion

20.	PSD is called?(a) Pressure Straight Desorption(b) Pressure Swing Distillation(c) Pressure Singer Desorption(d) Parameter Swing DistillationThis question was posed to me in an interview for job.The question is from Azeotropic Elements topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer»

Discussion

21.	Homogeneous azeotropes exist when the vapor is in equilibrium with?(a) Single liquid phase(b) Single Solid phase(c) Dual Phase(d) Triple PhaseThe question was posed to me during an online exam.I would like to ask this question from Azeotropic Distillation topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct ANSWER is (a) Single liquid PHASE Explanation: Homogeneous azeotropes exist when the vapor is in equilibrium with a single liquid phase. In a homogeneous system, ENTRAINER must be recovered by EXTRACTION.

Discussion

22.	An example of Minimum azeotrope is?(a) Benzene and Water(b) Ethanol and Water(c) Water and Ethyl Alcohol(d) Benzene and AlcoholThis question was addressed to me by my college director while I was bunking the class.My question is from Azeotropic Distillation topic in division Azeotropic and Extractive Distillation of Distillation Design
Answer» The correct choice is (b) Ethanol and WATER For explanation: Ethanol and water form a minimum-boiling azeotrope with ethanol as the major component and therefore ethanol cannot be completely DEHYDRATED by CONVENTIONAL DISTILLATION.

Discussion

23.	Distillate flowrate (D) is used to control the level in?(a) Rampage(b) Reflux(c) Reboiler(d) Condenser drumI had been asked this question by my college professor while I was bunking the class.This key question is from Extractive Distillation Terminology topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» CORRECT ANSWER is (d) Condenser drum For explanation: DISTILLATE FLOWRATE (D) is used to control the level in condenser drum, for the EXTRACTIVE middle vessel batch distillation column.

Discussion

24.	The crucial difference compared to homozeotrope distillation is that, a heteroazeotrope can be separated by?(a) Decantation(b) Depurification(c) Dehydration(d) DecansingThis question was addressed to me in quiz.I'm obligated to ask this question of Extractive Distillation topic in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct option is (a) Decantation Explanation: The CRUCIAL DIFFERENCE compared to homoazeotropic distillation is that a heteroazeotrope can be separated EASILY by decantation, this also makes the PROCESS scheme simpler.

Discussion

25.	If the boiling temperature isobar exhibits, an extremal point then mixture is said to be(a) Fully azeotropic(b) Totally azeotropic(c) Tangentially azeotropic(d) Partially azeotropicThe question was posed to me in class test.Question is taken from Azeotropic Elements topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Right option is (C) TANGENTIALLY azeotropic Best explanation: If the boiling temperature ISOBAR exhibits an extremal point located at the pure component EDGES, i.e., at ZERO concentration for one or several of the components in the mixture.

Discussion

26.	An azeotrope occurs, when there is same _______(a) Bubble Point(b) Boiling Point(c) VLE Composition(d) Pressure EquilibriumThe question was asked during a job interview.My question is from Azeotropic Distillation topic in section Azeotropic and Extractive Distillation of Distillation Design
Answer» Right answer is (C) VLE Composition Explanation: An azeotrope occurs when the composition of a VAPOR in equilibrium with a LIQUID MIXTURE has the same composition as the liquid.

Discussion

27.	The azeotrope in the ethanol–water binary system has a composition of ____ ethanol.(a) 89%(b) 59%(c) 88%(d) 99%The question was posed to me during a job interview.Query is from Azeotropic Elements in section Azeotropic and Extractive Distillation of Distillation Design
Answer» Right ANSWER is (a) 89% To elaborate: The AZEOTROPE in the ethanol–water binary system has a composition of 89 MOLE per cent of ethanol, starting with a mixture CONTAINING a lower proportion of ethanol.

Discussion

28.	Esters are produced by reacting alcohols with?(a) Organic acids(b) Pure base(c) P-Xylene(d) PTAThe question was asked during a job interview.The question is from Azeotropic Distillation in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» CORRECT answer is (a) ORGANIC acids For explanation: Esters are produced by REACTING alcohols with organic acids. The reaction is reversible and therefore unless ONE of the products is removed.

Discussion

29.	Ideal mixture obeys Raoult’s law results in?(a) Minimum boiling azeotrope(b) Maximum boiling azeotrope(c) Tangential azeotrope(d) Ideal azeotropesThe question was posed to me in final exam.This interesting question is from Azeotropic Elements in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer» RIGHT answer is (d) Ideal azeotropes To explain: The components have SIMILAR PHYSIOCHEMICAL properties, the INTERMOLECULAR forces between IDENTICAL and different molecules (A-A, B-B and A-B) are equal.

Discussion

30.	The vapor-liquid equilibrium (VLE) condition which may be expressed as?(a) y = f (S, H, T)(b) y = f (P, T, x)(c) x = f (T, S)(d) y = f (J, S)The question was asked by my college director while I was bunking the class.My doubt is from Extractive Distillation topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Right option is (b) y = f (P, T, x) For explanation: Where x and y are the liquid and VAPOR COMPOSITIONS, and P and T are the SYSTEM pressure and temperature, RESPECTIVELY T and x are not independent at the equilibrium state.

Discussion

31.	Extractive distillation of ethanol and water is done using?(a) Benzene(b) Ethylene glycol(c) Alcohol(d) Any acidI have been asked this question in an international level competition.I'd like to ask this question from Extractive Distillation Terminology in division Azeotropic and Extractive Distillation of Distillation Design
Answer» Right CHOICE is (B) Ethylene GLYCOL For explanation I would SAY: Extractive DISTILLATION of ethanol and water using ethylene glycol as an entrainer is a classic example in the distillation literature.

Discussion

32.	Entrainer feed flowrate (E), is used to control?(a) 5/6 split(b) 7/8 split(c) ½ split(d) ¾ splitI had been asked this question during an online exam.I want to ask this question from Extractive Distillation Terminology topic in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» Correct option is (c) ½ split The BEST explanation: Entrainer feed FLOWRATE (E) is USED to CONTROL the 1/2 split in the extractive section for the extractive middle vessel batch DISTILLATION column.

Discussion

33.	High reflux “weakens”, the effect of the?(a) Stages(b) Trays(c) Entrainer(d) PlatesI had been asked this question in class test.Query is from Extractive Distillation Terminology in portion Azeotropic and Extractive Distillation of Distillation Design
Answer» RIGHT option is (c) ENTRAINER For explanation I would say: High REFLUX “weakens” the effect of the entrainer (E), there is a MINIMUM and a maximum reflux ratio in order to ACHIEVE acceptable separation between component 1 and E.

Discussion

34.	Permeate fluxes decrease, significantly with decreasing(a) Reflux ratio(b) Feed Concentrations(c) Boiling point(d) Bubble pointI had been asked this question in an interview for job.I would like to ask this question from Extractive Distillation topic in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer» The CORRECT answer is (B) Feed CONCENTRATIONS For EXPLANATION: Permeate FLUXES decrease significantly with decreasing feed concentrations, There is a trade-off between the permeate flux and selectivity.

Discussion

35.	Negative deviation from Raoult’s law results in?(a) Minimum boiling azeotrope(b) Maximum boiling azeotrope(c) Tangential azeotrope(d) Elliptical azeotropeThe question was asked during a job interview.This intriguing question originated from Azeotropic Elements topic in division Azeotropic and Extractive Distillation of Distillation Design
Answer» Right answer is (b) Maximum boiling AZEOTROPE Easy EXPLANATION: The ATTRACTION between different molecules (A-B) is the strongest, This MAY cause the formation of a maximum-boiling azeotrope.

Discussion

36.	A relative volatility close to unity could indicate the presence of?(a) Separation Point(b) Pinch Point(c) Deep Point(d) Extraction PointI got this question in a national level competition.Question is taken from Azeotropic Distillation topic in chapter Azeotropic and Extractive Distillation of Distillation Design
Answer»

Discussion

Explore topic-wise InterviewSolutions in .

Liquid reflux (L1), is used to control?(a) 1/E split(b) 1/2E split(c) 1/5E split(d) E splitI have been asked this question in quiz.I want to ask this question from Extractive Distillation Terminology in chapter Azeotropic and Extractive Distillation of Distillation Design

Ethanol is dehydrogenated oxidatively to acetaldehyde using a _____ Catalyst.(a) Ag(b) Pt(c) Pb(d) HgI had been asked this question at a job interview.I'm obligated to ask this question of Azeotropic Distillation topic in division Azeotropic and Extractive Distillation of Distillation Design

Liquid flow out of middle vessel (LM) is used to control?(a) 2/E(b) 7/E(c) 8/E(d) 1/EThis question was posed to me during a job interview.My question is taken from Extractive Distillation Terminology topic in section Azeotropic and Extractive Distillation of Distillation Design

A greater entrainer flowrate generally, yields better(a) Reflux(b) Boil up(c) Hold up(d) SeparationThe question was asked in quiz.This is a very interesting question from Extractive Distillation topic in portion Azeotropic and Extractive Distillation of Distillation Design

A minimum-boiling azeotrope can be formed by?(a) Azeotrope entrainer(b) Any chemical(c) Water(d) BenzeneThis question was posed to me in quiz.Origin of the question is Azeotropic Distillation in portion Azeotropic and Extractive Distillation of Distillation Design

The residue curves of an n component homogenous mixture is defined by?(a) n-1 ODE(b) n-2 ODE(c) n-3 ODE(d) n ODEThis question was posed to me in final exam.Query is from Extractive Distillation in portion Azeotropic and Extractive Distillation of Distillation Design

Young performed his azeotropic dehydration of alcohol by?(a) Continuous Method(b) Batch Method(c) Stage Method(d) Full MethodI got this question in final exam.I want to ask this question from Azeotropic Distillation in section Azeotropic and Extractive Distillation of Distillation Design

Bottom flowrate (B) is used to control the level in?(a) Rampage(b) Reflux(c) Reboiler(d) Condenser drumI have been asked this question in my homework.Asked question is from Extractive Distillation Terminology topic in portion Azeotropic and Extractive Distillation of Distillation Design

When y = E(x), where E is?(a) Mapping function(b) Entity function(c) Frequency function(d) Phase functionI had been asked this question in an internship interview.My question is from Extractive Distillation in chapter Azeotropic and Extractive Distillation of Distillation Design

For easy separation, the relative volatility αi,j tends to?(a) 0(b) 1(c) 1.5(d) 0.5This question was posed to me in an international level competition.This interesting question is from Azeotropic Elements topic in portion Azeotropic and Extractive Distillation of Distillation Design

An azeotrope occurs, when there is same _______(a) Bubble Point(b) Boiling Point(c) VLE Composition(d) Pressure EquilibriumThe question was asked during a job interview.My question is from Azeotropic Distillation topic in section Azeotropic and Extractive Distillation of Distillation Design

The azeotrope in the ethanol–water binary system has a composition of ____ ethanol.(a) 89%(b) 59%(c) 88%(d) 99%The question was posed to me during a job interview.Query is from Azeotropic Elements in section Azeotropic and Extractive Distillation of Distillation Design

Esters are produced by reacting alcohols with?(a) Organic acids(b) Pure base(c) P-Xylene(d) PTAThe question was asked during a job interview.The question is from Azeotropic Distillation in portion Azeotropic and Extractive Distillation of Distillation Design

Entrainer feed flowrate (E), is used to control?(a) 5/6 split(b) 7/8 split(c) ½ split(d) ¾ splitI had been asked this question during an online exam.I want to ask this question from Extractive Distillation Terminology topic in portion Azeotropic and Extractive Distillation of Distillation Design

High reflux “weakens”, the effect of the?(a) Stages(b) Trays(c) Entrainer(d) PlatesI had been asked this question in class test.Query is from Extractive Distillation Terminology in portion Azeotropic and Extractive Distillation of Distillation Design