Download GTU BE/B.Tech 2018 Winter 7th Sem New 2173612 Fundamentals Of Reaction Engineering Question Paper

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Subject Code: 2173612

GUJARAT TECHNOLOGICAL UNIVERSITY

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BE - SEMESTER-VII (NEW) EXAMINATION - WINTER 2018

Subject Name: Fundamentals of Reaction Engineering

Time: 10:30 AM TO 01:00 PM

Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

1. Q.1

   1. Differentiate elementary and non-elementary reactions. (03 MARKS)
   2. Write a short note on various reaction intermediates used to elucidate kinetics of non — elementary reactions. (04 MARKS)

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   3. Compare theories available for predicting the temperature dependency of reaction rate. (07 MARKS)

2. Q.2

   1. On doubling concentration of reactant rate of reaction triples. Find the order of reaction. (03 MARKS)
   2. Derive integrated form of rate expression for n™ order reaction (04 MARKS)

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   3. An aqueous solution of ethyl acetate is to be saponified with sodium hydroxide. The initial concentration of ethyl acetate is 5g/l and that of caustic is 0.1N. The values of second order reaction rate constant at 0 °C and 20 °C are k = 0.235 and 0.924 (I/mol min) respectively. The reaction is reversible. Calculate the time required to saponify 95% ester at 40 °C. (07 MARKS)

   OR

   1. For the reaction A — R — S estimate the maximum concentration of R and time at which maximum concentration of R occurs. (07 MARKS)

3. Q.3

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   1. Write on (i) Space time (ii) Space velocity (iii) Residence time (03 MARKS)
   2. For a gaseous feed of Cao = 100, Cgo = 200 enters an isothermal flow reactor. For Xa = 0.8. Find Ca, Cs and Xs (04 MARKS)
   3. Describe differential and integral method of analysis of rate data. (07 MARKS)

   OR

   1. Explain correlation between fractional conversion and Damkohler number for a first order gas phase reaction of constant volume. (03 MARKS)

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   2. Write a short note on batch reactor systems used in process industries with advantages and disadvantages. (04 MARKS)

4. Q4

   1. A parallel liquid phase reaction A — R (k1); A — S (k2) has rate constants ki =5 hr! and k> = 0.8 hr'l. Find the moles of R produced in 15 min. Take Cao = 8.5 mol/l. Cro=Cso =0 (07 MARKS)
   1. Explain (i) standard heat of formation (ii) standard heat of combustion (iii) standard heat of reaction (03 MARKS)

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   2. Establish concentration levels that needs to be maintained for a bi-molecular reaction inorder to maximize formation of desired product. (04 MARKS)
   3. Prove that for reaction of first order occurring in a system of N CSTR’s connected in series the behavior of overall system matches that of PFR. (07 MARKS)

   OR

   1. Differentiate overall fractional yield and selectivity. (03 MARKS)
   2. The standard heat of a gas phase reaction at 25 °C A +B — 2R is ?HS = ?HR (25°c) = - 50000 J indicating that reaction is strongly exothermic. It is desired to run this reaction at 1000 °C. What is the nature and value of heat of reaction at that temperature? The reaction components are Cpa=35J/mol K Cps=45J/mol K Cpr =70 J/mol K (04 MARKS)

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5. Q5

   1. An aqueous reactant stream (4 mol A/l) passes through a mixed flow reactor followed by a plug flow reactor. Find the concentration at exit of plug flow reactor if in mixed flow rector the concentration is 1 mol/l. The reaction is second order with respect to A and volume of plug flow reactor is three times volume of mixed flow reactor. (07 MARKS)
   1. Write a short note on catalyst deactivation (03 MARKS)
   2. Discuss essential properties required for a catalyst. (04 MARKS)

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   3. For decomposition of cumene to benzene synthesize a rate law considering surface reaction as rate determining step. (07 MARKS)

   OR

   1. N204 decomposes according to relation N204 (g) == NO2(g) At 27 °C and 1 atm, 20% of N2Oy is dissociated. Calculate equilibrium constant Kp. (Take basis as 1 mol of N2Oj4 gas) (03 MARKS)
   2. Differentiate modifiers and inhibitors. (04 MARKS)
   3. Mention the seven steps governing the rate of conversion of reactant to product in a catalytic reaction. (07 MARKS)

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Date: 03/12/2018

Total Marks: 70

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