Chemical Reaction Engineering and Technology Questions - Set 13 - ObjectiveBooks
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Chemical Reaction Engineering and Technology Questions - Set 13

Practice Test: Question Set - 13


1. In the hydrodealkylation of toluene to benzene, the following reactions occur:

    C7H8 + H2 → C6H6 + CH4
    2C6H6 
 C12H10 + H2

Toluene and hydrogen are fed to a reactor in a molar ratio 1:5.80% of the toluene gets converted and the selectivity of benzene(defined as moles of benzene formed/moles of toluene converted) is 90%. The fractional conversion of hydrogen is

    (A) 0.16
    (B) 0.144
    (C) 0.152
    (D) 0.136

2. For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by
    (A) A dirac delta function
    (B) A step function
    (C) A ramp function
    (D) None of the above

3. Promoter
    (A) Initiates a chemical reaction and is a catalyst by itself
    (B) Alters the position of equilibrium in a reversible reaction
    (C) Increases the number of active centers by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals
    (D) All (a), (b) and (c)

4. In case of a P.F.R., there
    (A) May be lateral mixing of fluid
    (B) Should not be any mixing along the flow path
    (C) Both (a) and (b)
    (D) Neither (a) nor (b)

5. In an ideal P.F.R. at steady state conditions
    (A) The composition of reactants remains constant along a flow path
    (B) The conversion of the reactant varies from point to point along a flow path
    (C) There is no lateral mixing of fluid
    (D) There may be diffusion along the flow path

6. The rate of the reaction, X → Y, quadruples when the concentration of 'X' is doubled. The rate expression for the reaction is, r = K Cxn, the value of 'n' in this case will be
    (A) 0
    (B) 1
    (C) 2
    (D) 3

7. The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the
    (A) Increased temperature reduces the activation energy
    (B) Fraction of molecules having threshold energy increases
    (C) Collision frequency increases
    (D) Value of threshold energy decreases

8. The rate of a homogeneous reaction is a function of
    (A) Temperature and pressure only
    (B) Temperature and composition only
    (C) Pressure and composition only
    (D) All temperature, pressure and composition

9. The order of a chemical reaction is
    (A) An experimentally determined quantity
    (B) Always equal to the total stoichiometric number of reactants
    (C) Never fractional
    (D) None of these

10. In autocatalytic reactions,
    (A) One of the reactants acts as a catalyst
    (B) One of the products acts as a catalyst
    (C) Catalysts have very high selectivity
    (D) No catalyst is used

11. The rate of reaction does not decrease appreciably as the reaction proceeds in case of __________ reactions.
    (A) Autocatalytic
    (B) Exothermic
    (C) Endothermic
    (D) Autothermal

12. The dispersion number of perfect mixed flow is
    (A) 0
    (B) > 150
    (C) 
    (D) < 2100

13. Space time in flow reactor is
    (A) Usually equal to the residence time
    (B) The reciprocal of the space velocity
    (C) A measure of its capacity
    (D) Both (a) and (b)

14. For series reaction, the relative yield
    (A) Is always greater for plug-flow reactor than for the single CSTR of the same volume
    (B) Statement in (a) is wrong
    (C) Decreases with increasing conversion
    (D) Both (a) and (c) hold good

15. With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be
    (A) Higher in P.F. reactor
    (B) Higher in CSTR
    (C) Same in both the reactors
    (D) Data insufficient; can't be predicted

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