Scheme – E

Sample Question Paper

Course Name : Diploma in Chemical Engineering

Course Code : CH

Semester : Fifth

Subject Title : Chemical Reaction Engineering

Marks : 100 Time : 03 Hrs

Instructions:

1. All questions are compulsory.

2. Illustrate your answers with neat sketches wherever necessary.

3. Figures to the right indicate full marks.

4. Assume suitable data if necessary.

5. Preferably, write the answers in sequential order.

Q.1 (a) Attempt any THREE of the following: 12 Marks

a) State first and second law of thermodynamics. Give the mathematical expression.

b) Define rate of reaction and rate constant. Give the units of rate constant for zero order

and first order reaction.

c) Define fractional conversion of A (XA) and fractional change in volume (ΣA).

d) Draw the diagram of fluidized bed reactor with catalyst regenerator. Write the

material balance equation for a reactor.

Q.1 (b) Attempt any ONE of the following: 06 Marks

a) Derive Van’t Hoff equation.

b) Define activation energy. Draw the diagram showing the activation energy for

exothermic and endothermic reversible reaction. What is the role of activation energy

in a chemical reaction.

Q.2 Attempt any two of the following: 16 Marks

a) Derive the temperature dependency of rate constant from collision theory.

b) Derive the relation for constant volume irreversible second order reaction

A + B Product using integral method of analysis.

c) For the reactor data given below, consider the series arrangement of MFR and PFR.

The intermediate conversion if 0.7 and final conversion is 0.8.

12206

FA0 = 0.083 gm.mol/s

xA - rA (gm.mol/lit.sec)

0 0.0053

0.1 0.0052

0.2 0.005

0.3 0.0045

0.4 0.004

0.5 0.0032

0.6 0.0025

0.7 0.0018

0.8 0.00125

0.85 0.001

Draw the two different types of arrangement. Find the total reactor volume in each case.

State in which case total volume is minimum.

Q.3 Attempt any FOUR of the following: 16 Marks

a) How the feasibility of chemical reaction is determined from Gibb’s free energy

change?

b) Differentiate order and molecularity of chemical reaction (any four points).

c) Write the steps for differential method of analysis of data.

d) When endothermic reaction is taking place in fixed bed reactor, chances of hot spot

formation is high. Give reason.

e) Based on Van’t Hoff equation, explain why decrease in temperature is not desirable

for endothermic reaction?

Q.4 (a) Attempt any THREE of the following: 12 Marks

a) Write the steps and equation for finding the entropy change when one mole of ice is

heated from -10°C to steam at 110°C.

b) Give the equation for temperature dependency of rate constant from

i) Arrhenius law ii) Thermodynamics iii) transition state theory iv) Collision theory

c) Draw the graph of concentration term vs time for

i) First order reaction ii) Autocatalytic reaction. Write the value of slope also.

d) Describe with example the method of catalyst preparation in which catalyst is

supported on carrier.

Q.4 (b) Attempt any ONE of the following: 06 Marks

a) After 8 minutes in a batch reactor, reactant A (CA0 = 1 mol/lit) is 80% converted.

After 18 minutes conversion is 90%. Find the rate of reaction (K and order both).

b) Compare MFR and PFR (any four points)

Q.5 Attempt any TWO of the following: 16 Marks

a) Derive the performance equation for constant volume batch reactor where first order

reaction takes place. Give the graphical representation also.

b) What is catalyst regeneration? State six different methods of catalyst regeneration.

c) Define law of mass action. Derive the relation between Gibb’s free energy change and

equilibrium constant.

Q.6 Attempt any four of the following: 16 Marks

a) For the hydrolysis of reactant A, rate constant at 60°C is 6.698 x 10-3

and activation

energy is 16200 calories. Calculate the rate constant at 80°C.

b) At 25°C rate constant for the hydrolysis of ethyl acetate by NaOH is 6.5 lit/mol.min.

Starting with concentration of base and ester of 0.03 mol/lit each, what proportion of

ester is hydrolyzed in 10 minutes.

c) How extent of reaction gets affected when pressure is decreased, for reactions whose

total number of moles of product is less than total number of moles of reactant?

d) How feed should be admitted when PFRs are connected in parallel?

e) Show graphically how to find conversion when MFRs of different sizes are connected

in series (arrangement is given and find the final conversion).