GATE CH topic:chemical-reaction-engineering PYQs & Answers — Page 5

Questions 41–50 of 70. Imported answers require independent review unless marked reviewed.

The square of Thiele modulus,

, is given by

, where

is the characteristic length of the catalyst pellet,

is the rate constant of a first order reaction, and

is the effective diffusivity of the species in the pores.

is a measure of

Your answerChoose one option.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The decomposition of acetaldehyde (X) to methane and carbon monoxide follows four-step free radical mechanism. The overall rate of decomposition of X is

where,

, and

denote the rate constants of the elementary steps, with corresponding activation energies (in kJ mol⁻¹) of 320, 40, and 0, respectively. The temperature dependency of the rate constants is described by Arrhenius equation.

denotes the concentration of acetaldehyde. The rate constant for the overall reaction is

. The activation energy for the overall reaction (in kJ mol⁻¹) is ________ (round off to nearest integer).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A feed stream containing pure species L flows into a reactor, where L is partly converted to M as shown in the figure.

Diagram for Chemical Engineering question 37

The mass flow rate of the recycle stream is 20% of that of the product stream. The overall conversion of L (based on mass units) in the process is 30%. Assuming steady state operation, the one-pass conversion of L (based on mass units) through the reactor is

Your answerChoose one option.

34.2%

30%

26.3%

23.8%

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An elementary liquid phase reversible reaction

is carried out in an ideal continuous stirred tank reactor (CSTR) operated at steady state. The rate of consumption of P,

(in mol liter

minute

), is given by

where

and

are the concentrations (in mol liter

) of P and Q, respectively.

The feed contains only the reactant P at a concentration of 1 mol liter

, and the conversion of P at the exit of the CSTR is 75% of the equilibrium conversion. Assume that there is no volume change associated with the reaction, and the temperature of the reaction mixture is constant throughout the operation. The space time (in minutes) of the CSTR is ________ (round off to 1 decimal place).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An exothermic, aqueous phase, irreversible, first order reaction,

is carried out in an ideal continuous stirred tank reactor (CSTR) operated adiabatically at steady state. Rate of consumption of Y (in mol liter

minute

) is given by

where

is the concentration of Y (in mol liter

), and

is the temperature of the reaction mixture (in K). Reactant Y is fed at 50 °C. Its inlet concentration is 1.0 mol liter

, and its volumetric flow rate is 1.0 liter minute

In addition, use the following data and assumptions:

Heat of the reaction = −4200 J mol

Specific heat capacity of the reaction mixture = 4.2 J g

Density of the reaction mixture = 1000 g liter

Heat of the reaction, specific heat capacity and density of the reaction mixture do not vary with temperature

Shaft work is negligible

If the conversion of Y at the exit of the reactor is 90%, the volume of the CSTR (in liter) is ________ (round off to 2 decimal places).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The liquid phase irreversible reactions,

and

, are carried out in an ideal continuous stirred tank reactor (CSTR) operating isothermally at steady state. The space time of the CSTR is 1 minute. Both the reactions are first order with respect to the reactant P, and

and

denote the rate constants of the two reactions. At the exit of the reactor, the conversion of reactant P is 60%, and the selectivity of Q with respect to R is 50%. The value of the first order rate constant

(in minute

) is ________ (correct up to one decimal place).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A catalytic gas phase reaction

is conducted in an isothermal packed bed reactor operated at steady state. The reaction is irreversible and second order with respect to the reactant P. The feed is pure P with a volumetric flow rate of 1.0 liter minute

and concentration of 2.0 mol liter

In addition, use the following assumptions:

The reactant and product are ideal gases

There is no volume change associated with the reaction

Ideal plug flow conditions prevail in the packed bed

When the mass of catalyst in the reactor is 4 g, the concentration of P measured at the exit is 0.4 mol liter

. The second order rate constant (in liter

mol

minute

) is ________ (correct up to one decimal place).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The desired liquid-phase reaction

is accompanied by an undesired side reaction

Four isothermal reactor schemes (CSTR: ideal Continuous-Stirred Tank Reactor; PFR: ideal Plug Flow Reactor) for processing equal molar feed rates of D and E are shown in figure. Each scheme is designed for the same conversion. The scheme that gives the most favorable product distribution is:

Your answerChoose one option.

Diagram for Chemical Engineering question 10

Diagram for Chemical Engineering question 10 (figure 2)

Diagram for Chemical Engineering question 10 (figure 3)

Diagram for Chemical Engineering question 10 (figure 4)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

For a first order reaction in a porous spherical catalyst pellet, diffusional effects are most likely to lower the observed rate of reaction for

Your answerChoose one option.

slow reaction in a pellet of small diameter

slow reaction in a pellet of large diameter

fast reaction in a pellet of small diameter

fast reaction in a pellet of large diameter

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The elementary, irreversible, liquid-phase, parallel reactions, 2A → D and 2A → U, take place in an isothermal non-ideal reactor. The C-curve measured in a tracer experiment is shown in the figure, where

is the concentration of the tracer in g/m³ at the reactor exit at time

(in min).

Diagram for Chemical Engineering question 45

The rate constants are

Liter/(mol min) and

Liter/(mol min). Pure A is fed to the reactor at a concentration of 2 mol/Liter. Using the segregated model, the percentage conversion in the reactor is __________ (rounded off to the nearest integer).

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE CH topic:chemical-reaction-engineering PYQs

Question 7

Question 24

Question 37

Question 44

Question 49

Question 50

Question 51

Question 10

Question 11

Question 45