Chemical Engineering Gate Yearwise 


Chemical Engineering Gate 2012 Questions with Answer

Ques 1 GATE 2012

In a throttling process, the pressure of an ideal gas reduces by 50%. If CP and Cv are the heat capacities at constant pressure and constant volume, respectively (γ=Cp/CV), the specific volume will change by a factor of

A

2

B

21/γ

C

2(γ-1)/γ

D

0.5


(a) is the correct answer.

Ques 2 GATE 2012

If the temperature of saturated water is increased infinitesimally at constant entropy, the resulting state of water will be

A

Liquid

B

Liquid - vapor coexistence

C

Saturated vapor

D

Solid


(a) is the correct answer.

Ques 3 GATE 2012

In a parallel flow heat exchanger operating under steady state, hot liquid enters at a temperature Th,in and leaves at a temperature Th,out. Cold liquid enters at a temperature Tc,in and leaves at a temperature Tc,out. Neglect any heat loss from the heat exchanger to the surrounding. If Th,in>>Tc,in then for a given time interval, which ONE of the following statements is true?

A

Entropy gained by the cold stream is GREATER than entropy lost by the hot stream

B

Entropy gained by the cold stream is EQUAL to the entropy lost by the hot stream

C

Entropy gained by the cold stream is LESS than the entropy lost by the hot stream

D

Entropy gained by the cold stream is ZERO


(a) is the correct answer.

Ques 4 GATE 2012

For an exothermic reversible reaction, which one of the following correctly describes the dependence of the equilibrium constant (K) with temperature (T) and pressure (P)?

A

K is independent of T and P

B

K increases with an increase in T and P

C

K increases with T and decreases with P

D

K decreases with an increase in T and is independent of P


(d) is the correct answer.

Ques 5 GATE 2012

An insulated, evacuated container is connected to a supply line of an ideal gas at pressure Ps, temperature Ts and specific volume vs. The container is filled with the gas until the pressure in the container reaches Ps. There is no heat transfer between the supply line to the container, and kinetic and potential energies are negligible. If Cp and CV are the heat capacities at constant pressure and constant volume, respectively (γ=Cp/Cv), then the final temperature of the gas in the container is

A

γTs

B

Ts

C

(γ-1)Ts

D

(γ-1)Ts/γ


(a) is the correct answer.

Ques 6 GATE 2012

Consider a binary liquid mixture at constant temperature T and pressure P. If the enthalpy change of mixing, ΔH=5x1x2, where x1 and x2 are the mole fraction of species 1 and 2 respectively, and the entropy change of mixing ΔS=-R[x1ln x1+x2ln x2] (with R=8.314 J/mol.K), then the minimum value of the Gibbs free energy change of mixing at 300 K occurs when

A

x1=0

B

x1=0.2

C

x1=0.4

D

x1=0.5


(d) is the correct answer.

Ques 7 GATE 2012

The half-life of an nth order reaction in a batch reactor depends on

A

only the rate constant

B

only the rate constant and the order of the reaction

C

only the rate constant and the initial reactant concentration

D

the rate constant, initial reactant concentration, and the order of the reaction


(d) is the correct answer.

Ques 8 GATE 2012

Consider the reaction scheme shown below
A ↔ B ↔ C.
Both the reactions are first-order. The activation energies for k1 and k2 are 80 and 20 kJ/mol respectively. To maximize the yield of B, it is preferable to use

A

CSTR and high temperature

B

PFR and high temperature

C

CSTR and low temperature

D

PFR and low temperature


(b) is the correct answer.

Ques 9 GATE 2012

The rate-controlling step for the solid-catalyzed irreversible reaction A+B⟶C is known to be the reaction of adsorbed A with adsorbed B to give adsorbed C. If Pi is the partial pressure of component i and Ki is the adsorption equilibrium constant of component i, then the form of the Langmuir-Hinshelwood rate expression will be

A

rate ∝PAPB/(1+KAPA+KBPB+KCPC)

B

rate ∝PAPB/(1+KAPA+KBPB+KCPC)2

C

rate ∝PAPB/(1+KAPA+KBPB+KCPC)0.5

D

rate ∝PAPB/PC


(b) is the correct answer.

Ques 10 GATE 2012

The elementary reversible exothermic gas-phase reaction A+3B ↔ 2C is to be conducted in a non-isothermal, non-adiabatic plug flow reactor. The maximum allowable reactor temperature is Tmax. To minimize the total reactor volume, the variation of reactor temperature (T) with axial distance from the inlet (z) should be

A

A

B

B

C

C

D

D


(c) is the correct answer.

Ques 11 GATE 2012

The first order liquid phase reaction A→P is conducted isothermally in a plug flow reactor of 5 liter volume. The inlet volumetric flow rate is 1 liter/min and the inlet concentration of A is 2 mole/liter. If the exit concentration of A is 0.5 mole/liter, then the rate constant, in min-1, is

A

0.06

B

0.28

C

0.42

D

0.64


(b) is the correct answer.

Ques 12 GATE 2012

The first order liquid phase reaction A→P is conducted isothermally in a plug flow reactor of 5 liter volume. The inlet volumetric flow rate is 1 liter/min and the inlet concentration of A is 2 mole/liter. The plug flow reactor is replaced by 3 mixed flow reactors in series, each of 2.0 liters volume. The exact conversion of A (in %) is

A

35.9

B

52.5

C

73.7

D

94.8


(c) is the correct answer.

Ques 13 GATE 2012

In petroleum refining, catalytic reforming is used to convert

A

Paraffins and naphthenes to aromatics

B

Paraffins to hydrogen and carbon monoxide

C

Gas oil to diesel and gasoline

D

Light olefins to gasoline


(a) is the correct answer.

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