Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments where the ratio of concentration of B to that of A in the initial feed was less than 0.5, the concentration of B increased first, reached a maximum and then declined with time. However, for all experiments where this concentration ratio was 0.5 or above, concentration of B decreased monotonically with time right from the beginning. What is the ratio of the two rate constants (k1/k2) ?

Related Mcqs:

1. 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

2. In a chemical reaction as shown in the bellow figure, it is observed that the (i) Rate of formation of ‘P’ is doubled on doubling the concentration of ‘X’ (ii) Rate of formation of ‘P’ is quadrupled on doubling the concentration of ‘Y’ (iii) Doubling the concentration of ‘Z’ does not affect the rate of formation of ‘P’ What is the order of the above chemical reaction ?

   A. Zeroth order
   B. First order
   C. Second order
   D. Third order

3. 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 behaviour 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)

4. A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m3 and volumetric flow rate 1m3 /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m3. The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 k.mole/m3, the volume of the mixed flow reactor should be increased by a factor of_______________?

   A. 7
   B. 6
   C. 3
   D. 7/3

5. 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

6. With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion)?

   A. Increases
   B. Decreases
   C. Remain same
   D. Increases linearly

7. At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenius law is used. What will be this ratio, if transition state theory is used with the same value of „E/R‟ ?

   A. 1.6
   B. 2
   C. 2.24
   D. 2.5

8. 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

9. The gas phase reaction 2A ⇌ B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole % A and 20 mole % inerts. If the conversion of A at the reactor exit is 50%, then CA/CA0 at the outlet of the reactor is _______________________?

   A. 2/3
   B. 5/8
   C. 1/3
   D. 3/8

10. A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is_______________________?

    A. d(VCA)/dt = -F (CAF – CA) – kCA2V
    B. d(VCA)/dt = F (CAF – CA) – kCA2V
    C. d(VCA)/dt = -FCA – kCA2V
    D. d(VCA)/dt = FCAF – kCA2V