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# Multiple choice question for engineering

## Set 1

1. Brinkley Method can be used for,
i) Distillation
ii) Leaching
iii) Absorption
a) True
b) False

Answer: a [Reason:] This method is suitable for all the three operations, distillation for two components or more, leaching based on extraction purpose and similarly absorption for interfacial balance.

2. The hi is defined as the
a) Correlating factor
b) Correction Factor
c) Striping Factor
d) Relating Factor

Answer: a [Reason:] The correlating factor is defines as by hi, while L/V is defined as the stripping factor of systems.

3. The Smith-Brinkley (SB) method, is based on an analytical solution of the
a) Infinite-difference equations
b) Differential Equations
c) Integration
d) Finite-difference equations

Answer: d [Reason:] The Smith-Brinkley (SB) method, is based on an analytical solution of the finite-difference equations that can be written for staged separation processes.

4. The Smith-Brinkley (SB) method, rates a column on basis of
a) Initial sequence of the stages
b) Reverse sequence of its stages
c) Forward sequence of its stages
d) Straight Sequence

Answer: b [Reason:] The Smith-Brinkley (SB) method rates a column on basis of Reverse sequence of its stages, so to obtain top to bottom approach.

5. For a change in temperature ______ is added to tn.
a) Half
b) One fourth
c) Two third
d) Square

Answer: a [Reason:] For a change in temperature half is added to tn and half to tm, this acts as an average value between them¬ provides accuracy.

6. Smith Brinkley method is valuable for
a) Off-line optimization
b) Reflux optimization
c) On-line optimization
d) In-line optimization

Answer: c [Reason:] Smith Brinkley method is valuable for On-line optimization, while NR for the reflux Reflux optimization.

7. If the feed temperature is 211oK and Dew point is 70oF, then tn is
a) 68oF
b) 178oF
c) 140.5oF
d) 259.5oF

Answer: c [Reason:] As tn= (70+211)/2 = 140.5oF.

8. If the feed temperature is 2110K and Bubble point is 70oF, then tm is
a) 68oF
b) 178oF
c) 140.5oF
d) 259.5oF

Answer: d [Reason:] As tM= (308+211)/2 = 259.5oF.

9. Ki are determined at the
a) Top section Temperatures
b) Bottom section Temperatures
c) Middle section Temperatures
d) Right section Temperatures

Answer: a [Reason:] Ki are determined at the Top section Temperatures, and the pressure are determined at the left and right of column respectively.

10. K’I are determined at
a) Top section Temperatures
b) Bottom section Temperatures
c) Middle section Temperatures
d) Right section Temperatures

Answer: b [Reason:] K’I are determined at Bottom section Temperatures, this also involves calculation of K value for a given step response function.

## Set 2

1. Global method is also called as
a) Simultaneous regression method
b) Simultaneous rigorous method
c) Simultaneous correction method
d) Simultaneous matrix method

Answer: c [Reason:] Global method is also called as Simultaneous correction method, the 2N, NR and RF method are called as simultaneous rigorous method and Jacobin method as matrix method.

2. In global Newton method, all equations are solved together in
a) Regula falsi technique
b) 2N technique
c) Newton Raphson technique
d) False technique

Answer: c [Reason:] In global Newton method, all equations are solved together in Newton Raphson technique, false technique is used in Regula falsi method.

3. In global Newton method, The K value is
a) Coupled
b) Decoupled
c) Extreme
d) Bi-lateral

Answer: b [Reason:] In global Newton method, The K value is decoupled, as two values can lead to different calculations and thus only an average value is chosen.

4. Naphtali Sandholm method uses
a) MESH
b) LVF
c) RVF
d) TEMA

Answer: a [Reason:] Naphtali Sandholm method uses temperature and vapor from MESH, while TEMA is the standards used for the design of heat exchangers and other columns.

5. There are _______ equation in each stages.
a) C+1
b) 2C+2
c) 2C+1
d) None of the above

Answer: c [Reason:] There are 2C+1 Equation in each stages, there are total C components and thus from top to bottom each has two trays thus 2C+1 stages.

6. There are ______ equation in whole column.
a) 2C+1
b) N (2C+1)
c) N (2C-1)
d) C-1

Answer: b [Reason:] There are N (2C+1) Equation in whole column, Carrying C components and N stages the total number of equation becomes the product of both quantities.

7. The functions and variables are of size
a) N (2C+1) X N (2C+1)
b) N (2C+1) X N (2C-1)
c) N (2C+1) X N (2C)
d) N (2C+1) X N

Answer: a [Reason:] The functions and variables are of size N (2C+1) X N (2C+1) using Jacobin’s Method, as the Jacobin form is n X n thus this matrix implies the best.

8. QC is denoted as the
a) Heat capacity
b) Heat of Condenser
c) Heat released with cooling
d) Heat Collided

Answer: a [Reason:] QC is denoted as the Heat of Condenser, condenser is also considered as an alternative stage in the distillation column.

9. QR is denoted as the
a) Heat of reference
b) Heat of resemblance
c) Heat of rigorous
d) Heat of Reboiler

Answer: d [Reason:] QR is denoted as the Heat of Reboiler, the bottom product can cause heat losses thus loosing heat can cause failure thus reboiler heat QR is necessary.

10. In Naphtali Sandholm method, Absorption factor lij is denoted as
a) AijVij
b) Aij / Vij
c) Aij + Vij
d) Vij

Answer: a [Reason:] lij= AijVij in Naphtali Sandholm method, the multiplication of both quantities results in as matrix of i and j that can be solved easily using iterations.

## Set 3

1. Boston and Sullivan gave the concept of the
a) False method
b) Binary method
c) MESH Method
d) Inside Out Method

Answer: d [Reason:] Boston and Sullivan gave the concept of the Inside Out Method in 1973, MESH method involve the satisfaction of all equations.

2. ln Sbj is represented as
a) ln (KbjLJ/VJ)
b) ln (Kbj/VJ)
c) ln( KbjLJ)
d) ln (LJ)

Answer: a [Reason:] ln Sbj = ln (KbjLJ/VJ), this also resembles the same as the stripping factor that is used in the matrix calculations.

3. The vapors side product ln Rvj is given as
a) ln (KbjLJ/VJ)
b) ln (WbjLJ/VJ)
c) ln (KbjLJ/WJ)
d) ln (WJ)

Answer: b [Reason:] ln Rvj = ln (WjLJ/VJ) is the vapors side product, L and V respectively measuring the flow rates of liquid and gas streams.

4. The liqiud side product ln RLj is given as
a) ln (KbjLJ/VJ)
b) ln (Wbj/VJ)
c) ln (KbjLJ/WJ)
d) ln (WJ/LJ)

Answer: d [Reason:] RLj= ln (WJ/LJ) is the liquid side product, calculation of R factor for both components i and as well as j are equally important as that used in Sij.

5. For Russell method, ln Kbj is defined as
a) Aj – (Bj/Tj)
b) – (Bj/Tj)
c) Aj (Bj/Tj)
d) Aj + (Bj/Tj)

Answer: a [Reason:] For Russell method ln Kbj = Aj–(Bj/Tj), the Russell equations resembles the same as that of the Antoine equation for detecting vapor pressure.

6. For Boston method, ln Kbj
a) Aj + B (1j/Tj – 1/T*)
b) Aj – B (1j/Tj – 1/T*)
c) Aj – B (1j/Tj + 1/T*)
d) (1j/Tj + 1/T*)

Answer: b [Reason:] For Boston method ln Kbj = Aj – B (1j/Tj – 1/T*), this method is a revised version of the Russell method including T* i.e. equilibrium temperature.

7. HJ is defined as the
a) Ideal enthalpy
b) Total enthalpy
c) Final enthalpy
d) Pure enthalpy

Answer: a [Reason:] HJ is defined as the Ideal enthalpy based on liquid and gas compositions, while Hideal is defined as the ideal enthalpy.

8. HJ is formulated as
a) H* /ϫHVJ
b) H*- ϫHVJ
c) H* ( ϫHVJ)
d) H* + ϫHVJ

Answer: d [Reason:] HJ = H* + ϫHVJ, here H* is equilibrium enthalpy and which is added to the difference of x with the current enthalpy.

9. Total balance material balance is given as
a) αijSbj
b) αijHbj
c) αijDbj
d) αijVbj

Answer: a [Reason:] Total balance material balance SIJ = αijSbj,alpha is defined as the relative volatility and acts here as a correction factor.

10. The given function f(x) = x3-3X2+ 4 root is?
a) Negative
b) Positive
c) Unity
d) Zero

Answer: c [Reason:] The given plot is of f(x) = x3-3X2+ 4, calculating f(0)= 4 and f(1) =2 thus it is both negative and positive as the root does not change.

## Set 4

1. The component balance of the component A is given as
a) FzF= DxD + Wxw
b) FzF= DxD – Wxw
c) FzF= DxD/Wxw
d) FzF= DxD *Wxw

Answer: a [Reason:] According to McCabe Thiele method material balance over is given as FzF= DxD + Wxw, where F is the total feed.

2. If F= 200 kmol/h and ZF=0.4, XD=0.95, XW=0.04 and R=2.0, Then D is
a) 88.1
b) 22.6
c) 79.1
d) 158.2

Answer: c [Reason:] Using equation FzF= DxD + Wxw substituting values we get D=79.1.

3. The very First step of McCabe method is?
a) Plot the equilibrium curve
b) Plot diagonal curve
c) Plot Operating line
d) Plot stripping line

Answer: a [Reason:] Firstly we plot the Equilibrium diagram from the given equilibrium data, then the diagonal curve and then plot the operating line.

4. Calculate Boil up? If vapor flow and bottom withdrawal are 237.3 and 120.9 respectively
a) 1.5
b) 2.9
c) 2.111
d) 1.963

Answer: d [Reason:] As boil up is ratio of vapor flow and bottom withdrawal then 237.3/120.9 = 1.963.

5. If ZF¬=0.58 and also feed contains 35% mole of the liquid, then intercept of y axis is
a) 0.892
b) 0.205
c) 0.707
d) Can’t be calculated

Answer: a [Reason:] As – (ZF/q-1) using values -0.58/ (0.35-1) = 0.892.

6. If ZF=0.6 and also feed contains 72% mole of the liquid, then intercept of x axis is
a) 0.744
b) 0.899
c) 0.833
d) 1.2

Answer: c [Reason:] As (ZF/q) using values 0.6/ (0.72) = 0.833.

7. Calculate minimum reflux? If intercept is 0.56 and XD= 0.96
a) 0.174
b) 0.125
c) 0.21
d) 0.28

Answer: a [Reason:] As 0.56=XD/ (RM+1) = 0.96/ (RM+1) M= 0.174.

8. Slope of rectifying line is given by
a) R/XD
b) R/(R+1)
c) F/ (D+W)
d) R/(R+1)

Answer: b [Reason:] The rectifying line slope is always given as ratio of Reflux ratio plus unity i.e. R/(R+1), While R/XD gives us the reflux to liquid ratio for the operation.

9. If xD=0.95, xW= 0.04 and α=2.5. Find total trays?
a) 7
b) 6.7
c) 7.7
d) 6

Answer: b [Reason:] Using Fenske’s equation total number of trays to be calculate are 5.7 as Nm + 1 then 5.7+1 = 6.7 which is the final answer.

10. A Pinch point may occur at intersection of feed line and
a) Stream line
b) Stripping line
c) Rectifying line
d) Equilibrium line

Answer: d [Reason:] Pinch point always occurs at intersection of feed line and equilibrium line, while plot of x and y are called as the Equilibrium line.

## Set 5

1. Separation of a volatile mixture of relatively pure products, is done in a
a) Steam distillation
b) Fractionating Column
c) Flash Distillation
d) Depending of product required

Answer: d [Reason:] The separation always depends on the quality of product required independent of operation required.

2. McCabe Thiele is based on the assumption?
a) Constant molar overflow
b) Constant reflux ratio
c) Volatile products are used for better separation
d) Boil up ratio is infinity

Answer: a [Reason:] The best assumption of the McCabe Method is it is based on Constant molar overflow, while heat duties are neglected in the method.

3. The vapor rich section in the distillation column is called as
a) Rectifying Section
b) Boiling section
c) Stripping Section
d) Leaching section

Answer: a [Reason:] The part above the feed tray is rich in vapor which is called as rectifying or enriching section and contains only vapor in equilibrium with liquid.

4. The liquid rich section in a distillation column is called as
a) Boil up section
b) Reflux section
c) Stripping Section
d) Enriching Section

Answer: c [Reason:] The part below the feed tray is enriched with liquid feed which is called as Stripping Section and contains only liquid at the column temperature.

5. The feed of a distillation column is related to be a
a) Binary mixture
b) Urinary mixture
c) Mixture of phases
d) Tertiary Mixture

Answer: d [Reason:] Mixture of phases i.e. two phase mixture is necessary for distillation, either it can be a multicomponent mixture as per required conditions.

6. The equilibrium curve of the column is given as
a) yn=x
b) y*=x
c) yn+1=xn
d) xn+1=y

Answer: c [Reason:] The equilibrium curve is the locus of all equilibrium point given as yn+1=xn, while y*=x represents the equilibrium relation of gas and liquid.

7. The feed line equation is given by
a) F – L = q
b) L’ – L = qF
c) V – V’ =F
d) F = L – V

Answer: b [Reason:] The feed line equation is L’ – L = QF where q is the product of quantity of liquid contained in feed.

8. The overall Energy balance of a column is given by
a) V1HV1 = L0HL0 + DHD + QC
b) QC = V1HV1
c) V1HV1 = DHD + H0
d) Can change with models

Answer: a [Reason:] The energy balance equation is given as V1HV1 = L0HL0 + DHD + QC, where Qc is the heat provided through reboiler.

9. If the liquid flow rate is 212 and vapor flow rate is 284, then the slope of rectifying section is?
a) 0.55
b) 0.89
c) 1.33
d) 0.75

Answer: d [Reason:] As slope is given by L/V = 212/284 = 0.75.

10. If 0.75 is the fraction of liquid in the feed, Estimate the feed line slope?
a) -2.0
b) -1.5
c) -3.0
d) Cannot be calculated