GATE question papers: Chemical Engineering 2011 (CH)

Q. 1 – Q. 25 carry one mark each.

1.

Match the polymerization mechanisms in Group I with the corresponding polymers in Group II.

 

GROUP  I

 

GROUP  II

P.

Chain growth/addition polymerisation

I.

Polyethylene

Q.

Step growth / condensation polymerisation

II.

Polyvinyl chloride

 

 

III.

Polyethylene terephthalate

(A) P – III; Q – I, II                      

(B) P – I, II; Q – III,

(C) P – II, III; Q – I

(D) P – I; Q – II, III

2.

Which ONE of thee following sequences is arranged according to INCREASING calorific value?

(A) Producer gas, Natural gas, Water gas

(B) Natural gas, Producer gas, Water gas

(C) Producer gas, Water gas, Natural gas

(D) Water gas, Natural gas, Producer gas

3.

The CORRECT sequence of process equipment used in the production of sulphuric acid from sulphur by contact process is

(A)  burner, catalytic converter, 98% sulphuric acid absorption tower, oleum absorption column 

(B) catalytic converter, oleum absorption column, 98% sulphuric acid absorption tower, burner

(C)  burner, catalytic converter, oleum absorption column, 98% sulphuric acid absorption tower

(D)  burner, oleum absorption column, catalytic converter, 98% sulphuric acid absorption tower                       

4.

Hydrotreating is used for

(A) removal of water from crude oil,

(B) treatment of crude oil with water

(C) improving octane number of gasoline,

(D) removal of sulphur and nitrogen from petroleum fractions 

5.

Zeolite ZSM-5 is added to commercial FCC catalyst for

(A) promoting SO2 reduction

(B) promoting CO oxidation

(C) improving tolerance to metal content in feed

(D) enhancing Octane number

6. 

Minimum input required to calculate the 'blank diameter' for a torispherical head is

(A) crown radius,

(B) crown radius, knuckle radius and length of straight flange

(C)  knuckle radius and length of straight flange

(D) crown radius, and knuckle radius

7.  

Match the process parameters in Group I, with the measuring instruments in Group II.

 

GROUP  I

 

GROUP  II

P.

Flame temperature

I.

Thermocouple

Q.

Composition of LPG

II.

Radiation pyrometer

R.

Liquid air temperature

III.

Gas chromatograph

(A) P – III Q – I, R – II                       

(B) P – I, Q – III, R – II

(C) P – II, Q – III, R – I         

(D) P – II, Q – I, R – III

8.

The range of standard current signal in process instruments is 4 to 20 mA. Which ONE of the following is the reason for choosing the minimum signal as 4 mA instead of 0 mA?

(A) To minimize resistive heating in instruments,       

(B) To distinguish between signal failure and minimum signal condition

(C) To ensure a smaller difference between maximum and minimum signal

(D) To ensure compatibility with other instruments.

9.

Minimum work (W) required to separate a binary gas mixture at a temperature T0 and pressure P0 is 

W = -RT0  

where y and  y are mole fractions.  fpure.1 and fpure.2 are fugacities of pure species at T0 and P0 and and  are fugacities of species in the mixture at T0 , P and y1 If the mixture is ideal then  W  is

(A)   0                                                 

(B)  – RT0 [y1 ln y1 + y2 ln y2 ]

(C) RT0 [y1 ln y1 + y2 ln y2 ]              

(D)  RT0

10.

R is a closed planar region as shown by the shaded area in the figure below.  Its boundary C consists of the circles C1 and C2.

 

If  are all continuous everywhere in R. Green's theorem states that  Which ONE of the following alternatives CORRECTLY depicts the direction of integration along C?

 

11.

Which ONE of the following functions y (x) has the slope of its tangent equal to ?

Note: a and b are real constants.

(A)

(B) y = ax + b

(C)

(D)

12.

Let λ1 =  – 1 and λ2 = 3 be the eigenvalues and and  be the corresponding eigenvectors of a real 2 ´ 2 matrix Given that , which ONE of the following matrixes represents?

(A)               

(B)

(C) 

(D) 

13.

The partial molar enthalpies of mixing (in J/mol) for benzene (component 1) and cyclohexane (component 2) at 300 K and 1 bar are given by  and  , where  x1  and  x2  are the mole fractions.  When  ONE mole of benzene is added to TWO moles of  cyclohexane, the enthalpy change (in J) is 

(A)  3600        

(B)  2400        

(C)  2000        

(D)  800

14.

One mole of methane is contained in a leak proof piston-cylinder assembly at 8 bar and 1000 K.  The gas undergoes isothermal expansion to 4 bar under reversible conditions.  Methane can be considered as an ideal gas under these conditions.  The value of universal gas constant is 8.314 J mol–1 K–1. The heat transferred (in kJ) during the process is 

(A)  11.52       

(B)  5.76         

(C)  4.15         

(D)  2.38

15.

Consider the following two cases of movement of particles. In Case I, the particle moves along the positive y-direction and in Case II, the particle moves along negative y-direction.  Gravity acts along the positive y-direction.  Which ONE of the following options corresponds to thee CORRECT directions of buoyancy acting on the particles?

 

            

(A)  Positive y–direction for both the case

(B)  Negative y–direction for Case I, positive y–direction for Case II

(C)  Negative y–direction for both the cases

(D)  Positive y–direction for Case I, negative y–direction for Case II

16.

Match the pumps in Group I with the corresponding fluids in Group II.

 

GROUP  I

 

GROUP  II

P.

Gear pump

I.

Highly viscous liquid

Q.

. Peristaltic pump

II.

Aqueous sterile liquid

 

 

III.

Slurry

(A) P – III ;      Q – I,              

(B) P – II,        Q – I,

(C) P – III, III,  Q – II             

(D) P – I,         Q – II

17.

Consider two black bodies with surfaces S1 (area = 1 m2) and S2 (area = 4 m2).  They exchange heat only by radiation.  40% of the energy emitted by S1 is received by S2 The fraction of energy emitted by S2 that is received by S1 is, 

(A)  0.05         

(B)  0.1           

(C)  0.4           

(D)  0.6

18.

In film type condensation over a vertical tube, local heat transfer coefficient is

(A)  inversely proportional to local film thickness

(B)  directly proportional to local film thickness

(C)  equal to local film thickness

(D)  independent of local film thickness

19.

Ammonia (component 1) is evaporating from a partially filled bottle into surrounding air (component 2).  The liquid level in the bottle and the concentration of ammonia at the top of the bottle are maintained constant.  Ni is the molar flux relative to a fixed location in space and Ji is the molar flux with respect to the average molar velocity of the constituent species in the gas phase.  Assume that air in the bottle is stagnant.  Which ONE of the following is CORRECT?   

(A)  N1 = constant, N2 = 0, J1 + J2  =  0

(B)  N1 + N2 = 0, J1 + J2 = 0    

(C)  N1 + N2 = 0, J1 = constant, J2 = 0 

(D) N1 = constant, N2 = 0, J1 = constant, J2 = 0

20.

Simultaneous heat and mass transfer is occurring in a fluid flowing over a flat plant.  The flow is laminar.  The concentration boundary layer will COINCIDE with the thermal boundary layer, when

(A)  Sc = Nu   

(B)  Sh = Nu   

(C)  Sh = Pr    

(D)  Sc = Pr

21.

Consider an irreversible, solid catalysed, liquid phase first order reaction.  The diffusion and the reaction resistances are comparable.  The overall rate constant (ko) is related to the overall mass transfer coefficient (km) and the reaction rate constant (k) as  

(A)        

(B)

(C)

(D) ko = k + km

22.

Reactant R forms three products X, Y and Z irreversibly, as shown below,

 

The reaction rates are given by rX = kX CR ,  rY = k and  rZ = kZ CR. The activation energies for formation of X, Y and Z are 40, 40 and 5 kJ/mol respectively.  The pre-exponential factors for all reactions are nearly same.  The desired conditions for MAXIMIZING the yield of X are  

(A)  high temperature, high concentration of R  

(B)  high temperature,  low concentration of R

(C)  low temperature, high concentration of R

(D)  low temperature, low concentration of R

23.

In an orifice meter, if the pressure drop across the orifice is overestimated by 5% then the PERCENTAGE error in the measured flow rate is

(A)  + 2.47

(B)  + 5

(C)  – 2.47

(D)  – 5

24.

Two systems are available for compressing 6 m3 /hr of ambient air to 10 bar. The first one uses a single stage compressor (K1) and the second one uses a multistage compressor with inter-stage cooling (K2).  Which ONE of the following statements is INCORRECT?

(A) K2 will have knockout pots in between the stages

(B) Discharge temperature of K1 will be higher than that of K2

(C) K2 will consume more power than K1

(D) Cost of K2 will be more than that of K1

25.

In a thin-walled cylindrical vessel of thickness t with inside radius r, the internal gauge pressure is p. The hoop stress and the longitudinal stress in the shell are sh and sl respectively.  Which ONE of the following statements is TRUE?

(A)

(B)

(C)

(D)

Q. 26 to Q. 55 carry two marks each

26.

Unit vectors in x and z directions areand respectively.  Which ONE of the following is the directional derivative of the function F (x, z) = ln (x2 + z2) at the point P: (4, 0), in the direction of  ?)

(A)  

(B)  

(C)  1             

(D) 

27.

Which ONE of the following choices is a solution of the differential equation given below?

Note :  c is a real constant

(A)

(B)

(C)

(D)

28.

The value of the improper integral  is

(A)  – 2p

(B)  0

(C)  p

(D)  2p

29.

Fuel cell stacks are made of NINE membrane electrode assembles (MEAs) interleaved between TEN bipolar plates (BPs) as illustrated below.  The width of a membrane electrode assembly and a bipolar plate are normally distributed with  μMEA = 0.15, σMEA = 0.01 and  μBP = 5, σBP = 0.1 respectively.  The widths of the different layers are independent of each other.

 

Which ONE of the following represents the CORRECT values of ( μstack , σstack ) for the overall fuel cell stack width? 

(A)  (51.35, 0.32)

(B)  (51.35, 1.09)

(C)  (5.15, 0.10)

(D)  (5.15, 0.11)

30.

In the fixed point iteration method for solving equations of the form x = g(x), the

(n +1)th iteration value is  xn+1 =g(xn), where xn represents the nth iteration value.  g(x) and corresponding initial guess value  x0 in the domain of interest are shown in the following choices.  Which ONE of these choices leads to a converged solution for x? 

31.

Ammonia is synthesized at 200 bar and 773 K by the reaction N2 + 3H2   2NH3. The yield of ammonia is 0.45 mol/mol of fresh feed.  Flow sheet for the process (along with available compositions) is shown below.

                     

 

The single pass conversion for H2 in the reactor is 20%.  The amount of H2 lost in the purge as a PERCENTAGE of H2 in fresh feed is

(A)  10            

(B)  20            

(C)  45            

(D)  55

32.

The following combustion reactions occur when methane is burnt.

CH4 + 2O2  CO2 + 2H2O

2CH4 + 3O2   2CO + 4H2O

20 % excess air is supplied to the combustor.  The conversion of methane is 80 % molar ratio of CO to CO2 in the flue gas is 1: 3.  Assume air to have 80 mol % N2 and rest O2. The O2 consumed as a PERCENTAGE of O2 entering the combustor is 

(A)  20          

(B)  62.5         

(C)  80            

(D)  83.3

33.

Consider a binary mixture of methyl ethyl ketone (component 1) and toluene (component 2).  At 323 K the activity coefficients γ1 and γ2 are given by

 

ln g1  =  1 – Ψ2 + 4Ψ2  x1),

ln g2  =   (Ψ1 + Ψ2  4 Ψ2  x2)

where x1 and x2  are the mole fractions in the liquid mixture, and Ψ1 and Ψ2 are parameters independent of composition.  At the same temperature, the infinite dilution activity coefficients, and  are given by ln  = 0.4 and ln  = 0.2.  The vapour pressure of methyl ethyl ketone and toluene at 323 K are 36.9 and 12.3 kPa respectively.  Assuming that the vapour phase is ideal, the equilibrium pressure (in kPa) of a liquid mixture containing 90 mol % toluene is

(A)  19            

(B)  18            

(C)  16            

(D)  15

34.

Two liquids (P and Q) having same viscosity are flowing through a double pipe heat exchanger as shown in the schematic below.

 

Densities of P and Q are 1000 and 800 kg/m3 respectively.  The average velocities of the liquids P and Q are 1 and 2.5 m/s respectively.  The inner diameters of the pipes are 0.31 and 0.1 m.  Both pipes are 5 mm thick.  The ratio of the Reynolds numbers ReP to ReQ is

(A)  2.5

(B)  1.55

(C)  1

(D)  4

35.

The particle size distributions of the feed and collected solids (sampled for same duration) for a gas cyclone are given below.

Size  range  (μm)

1–5

5–10

10–15

15–20

20–25

25–30

Weight of feed in the size range (g)

2.0

3.0

5.0

6.0

3.0

1.0

Weight of collected solids in the size range (g)

0.1

0.7

3.6

5.5

2.9

1.0

What is the collection efficiency (in PERCENTAGE) of the gas cyclone? 

(A)  31             (B)  60             (C)  65             (D)  69

36.

A liquid is flowing through the following piping network.  The length of pipe sections P, Q, R and S shown in the schematic are equal.  The diameters of the sections P and R are equal and the diameter of the section Q is twice that of S.  The flow is steady and laminar.  Neglecting curvature and entrance effects, the radio of the volumetric flow rate in the pipe section Q to that in S is

 (A)  16             (B)  8               (C)  2               (D)  1

37.

Oil at 120 °C is used to heat water at 30 °C in a 1–1 co-current shell and tube heat exchanger.  The available heat exchange area is S1.  The exit temperatures of the oil and the water streams are 90 °C and 60 °C respectively.  The co-current heat exchanger is replaced by a 1–1 counter -current heat exchanger having heat exchange area S2.  If the exit temperatures and the overall heat transfer coefficients are same, the ratio of S1 to S is 

(A)  ∞             (B)  1.1            (C)  0.91          (D)  0

38.

An aqueous sodium chloride solution (10 wt %) is fed into a single effect evaporator at a rate of 10000 kg/hr. It is concentrated to a 20 wt % sodium chloride solution.  The rate of consumption of steam in the evaporation is 8000 kg/hr.  The evaporator capacity (kg/hr) and economy are 

(A)  5000, 0.625          (B) 10000, 0.625         (C)  5000, 1.6       (D)  10000, 1.6 

39.

Heat is generated uniformly within a solid slab.  The slab separates fluid 1 from fluid 2.  The heat transfer coefficients between the solid slab and the fluids are h1 and h2 (h2 > h1) respectively.  The steady state temperature profile (T vs. x) for one-dimensional heat transfer is CORRECTLY shown by  

40.

A gas mixture is in contact with a liquid.  Component P in the gas mixture is highly soluble in the liquid.  Possible concentration profiles during absorption of P are shown in the choices, where

            x          :  mole fraction of P in bulk liquid

            y          :  mole fraction of P in bulk gas,

            x i         :  mole fraction of P at the interface in liquid

            y i         :  mole fraction of P at the interface in gas

            y*        :  equilibrium gas phase mole fraction corresponding to x i

            The CORRECT profile is

41.

A batch of 120 kg wet solid has initial moisture content of 0.2 kg water/kg dry solid. The exposed area for drying is 0.05 m2/kg dry solid.  The rate of drying follows the curve given below.

The time required (in hours) for drying this batch to a moisture content of 0.1 kg  water/kg dry solid is 

(A)  0.033                      (B)  0.43                        (C)  0.6                         (D)  2.31

42

For a first order catalytic reaction the Thiele modulus (f) of a spherical pellet is defined as

       f=  

where,  ρp  =     pellet  density                           Rs  =    pellet  radius

            De  =    effective diffusivity                     k  =      first order reaction rate constant

If  ф > 5, then the apparent activation energy (Ea) is related to the intrinsic (or true) activation energy (E) as

(A)  Ea =  E0.5                       (B)  Ea =  0.5 E               (C)  Ea =  2 E               (D)  Ea =  E2    

43

The following figures show the outlet tracer concentration profiles (c vs. t) for a pulse input.

 

 

Match the figures in Group I with the reactor configurations in Group II.

 

GROUP  I

 

GROUP  II

P.

Figure 1

I.

PFR

Q.

Figure 2

II.

CSTR

R.

Figure 3

III.

PFR and CSTR in series

 

 

IV.

PFR and CSTR in parallel

(A) P – II, Q – IV, R – III                    (B) P – IV, Q – III, R – I

(C) P – III, Q – IV, R – II                    (D) P – I, Q – III, R – II

44

The following diagram shows a CSTR with two control loops.  A liquid phase, endothermic reaction is taking place in the CSTR, and the system is initially at steady state.  Assume that the changes in physical properties of the system are negligible.

TC: Temperature controller, LC: Level controller, TT: Temperature transmitter, LT: Level transmitter, V1 and V2: Control valves.

Which ONE of the following statements is TRUE? 

(A)  Changing the level controller set point affects the opening of V2 ONLY

(B)  Changing the temperature controller set point affects the opening of V2 ONLY

(C)  Changing the temperature controller set point affects the opening of BOTH V1 and V2

(D)  Changing the level controller set point affects the opening of BOTH V1 and V2

45

A process plant has a life of 7 years and its salvage value is 30 %.  For what MINIMUM fixed-percentage factor will the depreciation amount for the second year, calculated by declining balance method be EQUAL to that calculated b the straight line depreciation method? 

(A)  0.1                        (B)  0.113                    (C)  0.527                    (D)  0.887

46

A continuous fractionator system is being designed.  The following cost figures are estimated for a reflux ratio of 1.4.  

Fixed cost including all accessories (Rs.) for 

Operating cost (Rs./year) for 

Column

Condenser

Reboiler

Condenser cooling water

Reboiler heating steam

6 ´ 106

2 ´ 106

4 ´ 106

8 ´ 106

1 ´ 106

The annualized fixed charge is 15 % of the fixed cost.  The total annualized cost (in Rs.) is

(A)  10.8 × 106                        (B)  13.35 × 106

(C)  15.9 × 106                        (D)  3.15 ×106

47

Match the reactions in Group I with the products in Group II.

 

GROUP  I

 

GROUP  II

P.

Ammoxidation

I.

Aniline from benzene

Q.

Nitration

II.

Benzoic acid from toluene

R.

Dehydrogenation

III.

Acrylonitrile from propylene

S.

Oxidation

IV.

Styrene from ethylbenzene

(A) P – III, Q – I, R – IV, S – II          (B) P – IV, Q – I, R – III, S – II

(C) P – I, Q – III, R – IV, S – II          (D) P – I, Q – II, R – III, S – IV

Common  Data  Questions

Common Data for Questions 48 and 49 :

For a liquid flowing through a packed bed, the pressure drop per unit length of the bed   is

            

where, is the superficial liquid velocity, ε is the bed porosity,  is average particle size, fs is particle sphericity,  rf is liquid density and  μf  is liquid viscosity.

Given data :   = 1 × 10–3 m, fs = 0.8  ρf  = 1000 kg/m,  μ = 1 x 10–3 kg m–1 s–1,

particle density,  rp  = 2500 kg/m3 and acceleration due to gravity,  g = 9.8 m/s2

48

When  is 0.005 m/s and ε = 0.5, which ONE of the following is the CORRECT value for the ratio of the viscous loss to the kinetic energy loss? 

(A)  0.09                      (B)  1.07                      (C)  10.71                    (D)  93

49

On further increasing, incipient fluidization is achieved.  Assuming that the porosity of the bed remains unaltered, the pressure drop per unit length (in Pa/m) under incipient fluidisation condition is 

(A)  3675                     (B)  7350                     (C)  14700                   (D)  73501

Common Data for Questions 50 and 51 :

A binary feed mixture containing equimolar quantities of components S and T is to be distilled in a fractionating tower at atmospheric pressure. The distillate contains 96 mol % S.  The q-line (feed line) intersects the equilibrium line at x¢ = 0.46 and y¢ = 0.66, where x¢ and y¢ are mole fractions.  Assume that the McCabe-Thiele method is applicable and the relative volatility is constant.

50

The MINIMUM reflux ratio is

(A)  1.6                        (B)  1.5                        (C)  0.66                      (D)  0.6

51

The feed is

(A) at dew point                                   (B) at bubble point

(C) superheated vapour                        (D) partially vapour

Linked Answer Questions

Linked Answer Questions 52 and 53 :

52

In an aqueous solution, reaction P Q occurs under isothermal conditions following first order kinetics.  The feed rate is 500cm3/min and concentration of P in the feed is

1.5 x 10–4 mole/cm3.  The reaction is carried out in a 5 litre CSTR.  At steady state, 60 % conversion is observed.  The rate constant (in min–1) is 

(A)  0.06                      (B)  0.15                      (C)  0.21                      (D)  0.28

53

The 5 litre CSTR is replaced by five CSTRs in series.  If the capacity of each new CSTR is 1 litre, then the overall conversion (in %) is 

(A)  65                         (B)  67             (C)  73             (D)  81

Statement for Linked Answer Questions 54 and 55 :

A PID controller output p(t), in time domain, is given by

where e(t) is the error at time t.  The transfer function of the process to be controlled is .  The measurement of the controlled variable is instantaneous and accurate.

54

The transfer function of the controller is

(A)

(B)

(C)

(D)

55

The characteristic equation of the closed loop is

(A) 6s2 + 102s +1 = 0                      (B) 700s2 + 102s + 25 = 0

(C) 100s2 – 196s – 25 = 0                 (D) 240s3 + 812s2 + 204s + 1 = 0

General Aptitude (GA) Questions

Q. 56 – Q. 60 carry one mark each.

56

Choose the most appropriate word(s) from the options given below to complete the following sentence.

I contemplated ________ Singapore for my vacation but decided against it.

(A) to  visit                                          (B) having to visit

(C) visiting                                           (D) for a visit

57

If Log (P) = (1/2) Log (Q) = (1/3) Log (R), then which of the following options is TRUE?

(A) P2  =  Q3 R2                                   (B) Q2  =   P R

(C) Q2  =  R3 P                                     (D) R  =  P2 Q2

58

Which of the following options is the closest in the meaning to the word below : 

Inexplicable

(A) Incomprehensible                           (B) Indelible

(C) Inextricable                                    (D) Infallible

59

Choose the word from the options given below that is most nearly opposite in meaning to the given world :

Amalgamate

(A) merge                                            (B) split

(C) collect                                            (D) separate

60

Choose the most appropriate word from the options given below to complete the following sentence.

If you are trying to make a strong impression on your audience, you cannot do so by being understated, tentative or __________

(A) hyperbolic                                      (B) restrained

(C) argumentative                                (D) indifferent

Q. 61 to Q. 65 carry two marks each.

61

The variable cost (V) of manufacturing a product varies according to the equation V = 4q, where q is the quantity produced.  The fixed cost (F) of production of same product reduces with q according to the equation F = 100/q.  How many units should be produced to minimize the total cost (V + F)? 

(A)  5              (B)  4               (C)  7               (D)  6

62

P, Q, R and S are four types of dangerous microbes recently found in a human habitat.  The area of each circle with its diameter printed in brackets represents the growth of a single microbe surviving human immunity system within 24 hours of entering the body.  The danger to human beings varies proportionately with the toxicity, potency and growth attributed to a microbe shown in the figure below:

A pharmaceutical company is contemplating the developing of a vaccine against the most dangerous microbe.  Which microbe should the company target in its first attempt? 

(A)  P              (B)  Q              (C)  R              (D)  S

63

Few school curricula include a unit on how to deal with bereavement and grief, and yet all students at some point in their lives suffer from losses through death and parting.

Based on the above passage which topic would not be included in a unit on bereavement? 

(A)  how to write a letter of condolence

(B)  what emotional stages are passed through in the healing process

(C)  What the leading causes of death are

(D)  how to give support to a grieving friend

64

A container originally contains 10 litres of pure spirit.  From this container 1 litre of spirit is replaced with 1 litre of water.  Subsequently, 1 litre of the mixture is again replaced with 1 litre of water and this process is repeated one more time.  How much spirit is now left in the container? 

(A)  7.58 litres             (B)  7.84 litres              (C)  7 litres                   (D)  7.29 litres

65

A transporter receives the same number of orders each day.  Currently, he has some pending orders (backlog) to be shipped.  If he uses 7 trucks, then at the end of the 4th day he can clear all the orders.  Alternatively, if he uses only 3 trucks, then all the orders are cleared at the end of the 10th day.  What is the minimum number of trucks required so that there will be no pending order at the end of the 5th day?

(A)  4              (B)  5               (C)  6               (D)  7

 

End of Question Paper