Basics of Chemical Reaction & Reactor Engineering MCQ - Set 06 - ObjectiveBooks

Basics of Chemical Reaction & Reactor Engineering MCQ - Set 06

Practice Test: Question Set - 06

1. In case of calcination of limestone, CaCO3 CaO + CO2, the addition of more of CaO will result in __________ in the concentration of CO2.
    (A) No change
    (B) Increase
    (C) Decrease
    (D) Unpredictable from the data

2. Concentration of the limiting reactant (with initial concentration of a moles/liter) after time t is (a-x). Then 't' for a first order reaction is given by
    (A) k. t = ln a/(a - x)
    (B) k. t = x/a (a - x)
    (C) k. t = ln (a - x)/a
    (D) k. t = ln a (a - x)/x

3. Exposure of a photographic plate to produce a latent image is an example of __________ reaction.
    (A) Very slow
    (B) Very fast
    (C) Photochemical
    (D) Both (b) and (c)

4. A batch reactor is characterized by
    (A) Constant residence time
    (B) Variation in extent of reaction and properties of the reaction mixture with time
    (C) Variation in reactor volume
    (D) Very low conversion

5. Knudsen diffusion is directly proportional to
    (A) T
    (B) √T
    (C) 1/√T
    (D) T2

6. Promoter is added to the catalyst to improve its
    (A) Porosity
    (B) Sensitivity
    (C) Surface area
    (D) None of these

7. In a chemical reaction, represented by as shown in the bellow figure, it is observed that the
(i) Rate of reaction increases by a factor of 4 on doubling the concentration of the reactant.
(ii) Rate of reaction increases by a factor of 9 on trebling the concentration of the reactant.

Then the rate of the reaction is proportional to (where, CA = concentration of the reactant)

    (A) CA
    (B) CA2
    (C) CA3
    (D) CA4

8. Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure?
    (A) Langmuir adsorption isotherm
    (B) Adsorption isobar
    (C) Freundlich adsorption isotherm
    (D) None of these

9. Mean residence time is equal to the space time, when
    (A) The feed rate is measured at temperature and pressure in the reactor
    (B) The temperature, pressure and the density of reaction mixture remains constant throughout the reactor
    (C) There is no change in number of moles in gaseous reaction
    (D) All (a), (b) and (c)

10. Calcination reaction of limestone (CaCO3 → CaO + CO2) goes to completion in the rotary kiln, because
    (A) CaO is not dissociated
    (B) CO2 escapes continuously
    (C) Of high calcination temperature
    (D) CaO is more stable than CaCO3

11. The following gas phase reaction is taking place in a plug flow reactor.
A stoichiometric mixture of A and B at 300 K is fed to the reactor. At 1 m along the length of the reactor, the temperature is 360 K. The pressure drop is negligible and an ideal gas behavior can be assumed. Identify the correct expression relating the concentration of A at the inlet (CA0), concentration of A at 1m (CA) and the corresponding conversion of A (X).
    (A) CA = 1.2 CA0 (1 - X)/(1 - 0.33X)
    (B) CA = 1.2 CA0 (1 - X)/(1 - 0.5X)
    (C) CA = 0.83 CA0 (1 - X)/(1 - 0.33X)
    (D) CA = 0.83 CA0 (1 - X)/(1 - 0.5X)

12. A catalyst inhibitor
    (A) Lessens its selectivity
    (B) May be useful for suppressing undesirable side reactions
    (C) Is added in small quantity during the catalyst manufacture itself
    (D) All (a), (b) and (c)

13. A catalyst in a chemical reaction
    (A) Decreases the activation energy
    (B) Alters the reaction mechanism
    (C) Increases the frequency of collisions of reacting species
    (D) All (a), (b) and (c)

14. A batch reactor suffers from following disadvantage.
    (A) Poor product quality control
    (B) High labour and handling cost
    (C) High shutdown time requirement for emptying, cleaning and refilling
    (D) All (a), (b) and (c)

15. An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4kmole/m3 of each A and B enters the reactor at 8m3 /hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed?
    Data: Heat of reaction = - 50 kJ/mole
    Density of the reacting mixture = 1000kg/m3
    Specific heat of reacting mixture = 2kJ/kg.K 

The above data can be assumed to be independent of temperature and composition.
    (A) 190
    (B) 290
    (C) 390
    (D) 490

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