chemical engineering chemical reaction Mcqs
1. For identical flow rate, feed composition and for elementary first order reactions, N equal sized mixed reactors in series with a total volume V gives the same conversion as a single plug flow reactor of volume V for constant density systems. This is true, when the value of N is ___________________?
comments icon0

A. ? 1

B. ?

C. > 1

D. 1

2. Overall rate of reaction in a heterogeneous catalytic reaction depends upon the mass and energy transfer from the fluid to solid surface and its rate of reaction is usually ________________ the concentration of catalyst, if it does not entail a chain mechanism?
comments icon0

A. Proportional to the square of

B. Proportional to

C. Inversely proportional to

D. Independent of

3. Bulk diffusion in catalyst pore _______________ with increase in pressure?
comments icon0

A. Increases exponentially

B. Remains unchanged

C. Decreases

D. Increases

4. The equilibrium constant K of a chemical reaction depends on_________________?
comments icon0

A. Pressure only

B. Temperature and pressure

C. Ratio of reactants

D. Temperature only
5. Autocatalytic reactions are best carried out in a_________________?
comments icon0

A. Plug flow reactor

B. Recycle reactor

C. CSTR in series

D. CSTR

6. Velocity of a chemical reaction___________________?
comments icon0

A. Decreases with increase of reactant concentration

B. Increases with increase of pressure of reactants for all reactions

C. None of these

D. Decreases with increase in temperature

7. When a catalyst increases the rate of chemical reaction, the rate constant_____________________?
comments icon0

A. Become infinite

B. Remain constant

C. Increases

D. Decreases

8. Arrhenius equation shows the variation of ___________________ with temperature?
comments icon0

A. Reaction rate

B. Rate constant

C. Frequency factor

D. Energy of activation

9. The reaction between oxygen and organic material is a/an _____________ reaction?
comments icon0

A. Endothermic

B. Photochemical

C. Exothermic

D. Biochemical

10. A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be ____________________ minutes?
comments icon0

A. 4

B. 12

C. 16

D. 8

11. The half life period t of a zero order reaction as shown in the bellow figure, is equal to_________________?
comments icon0

A. 0.693/K

B. CA0/2K

C. CA0/K

D. 1/K

12. Half life period of a chemical reaction is proportional to CA0 -1, if the reaction is of _______________ order?
comments icon0

A. Third

B. First

C. Second

D. Zero

13. Which of the following will give maximum gas conversion ?
comments icon0
A. Semi-fluidised bed reactor

B. Fixed bed reactor

C. Plug-flow catalytic reactor

D. Fluidised bed reactor

14. Promoter is added to the catalyst to improve its____________________?
comments icon0

A. Surface area

B. None of these

C. Porosity

D. Sensitivity
15. In case of calcination of limestone, CaCO3 CaO + CO2, the addition of more of CaO will result in _______________ in the concentration of CO2?
comments icon0

A. Increase

B. No change

C. Unpredictable from the data

D. Decrease

16. On application of pressure to the equilibrium system, ice ? water; which of the following phenomenon will occur ?
comments icon0
A. More water will be formed

B. More ice will be formed

C. Water will evaporate

D. Equilibrium will not be attained

17. What is the order of a chemical reaction in which doubling the initial concentration of the reactants doubles the half life time of the reaction ?
comments icon0
A. 0

B. 2

C. 3

D. 1

18. A space velocity of 5 hr-1 means that ___________________?
comments icon0

A. Cent per cent conversion can be achieved in at least 5 hours

B. Five reactor volumes of feed (at specified conditions) are being fed into the reactor per hour

C. After every 5 hours, reactor is being filled with the feed

D. A fixed conversion of a given batch of feed takes 5 hours

19. For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant ?
comments icon0
A. Increases with pressure

B. Increases /decreases with pressure depending on the stoichiometric co-efficients of the

C. Decreases with pressure

D. ction

E. Is independent of pressure

20. Rate of a chemical reaction is independent of the concentration of the reactants for a _________________ reaction?
comments icon0

A. None of these

B. Zero order

C. Consecutive

D. Third order

21. The rate of a homogeneous reaction is a function of__________________?
comments icon0

A. Temperature and composition only

B. Pressure and composition only

C. Temperature and pressure only

D. All temperature, pressure and composition
22. For all positive reaction orders for a particular duty ?
comments icon0
A. Mixed reactor is always larger than the plug-flow reactor

B. Reactor size is independent of the type of flow

C. Ratio of the volume of the mixed reactor to that of the plug-flow reactor decreases with order

D. Density variation during reaction affects design

23. Unreacted core model represents the reaction involving ______________________?
comments icon0

A. None of these

B. Roasting of sulphide ores

C. Combustion of coal particles

D. Manufacture of carbon disulphide from elements

24. What is the dispersion number for a CSTR ?
comments icon0
A. ?

B. < 1

C. 0

D. 1

25. In which of the following gaseous phase reactions, the equilibrium of the reaction remains unaffected by pressure changes ?
comments icon0

A. 2O3 ? 3O2

B. 2SO2 + O2 ? 2SO3

C. N2 + O2 ? 2NO

D. 2NO2 ? N2O4

26. For a _____________ order reaction, the units of rate constant and rate of reaction are the same ?
comments icon0

A. Second

B. Zero

C. First

D. Fractional

27. The rate of the reaction, X ? Y, quadruples when the concentration of X is doubled. The rate expression for the reaction is, r = K Cx n, the value of n in this case will be_______________________?
comments icon0
A. 2

B. 0

C. 1

D. 3

28. B.E.T. method can be used to determine the ___________________ of a porous catalyst?
comments icon0
A. Surface area

B. Pore volume

C. All A., B. and C.

D. Solid density

29. Chemical kinetics can predict the _______________ of a chemical reaction?
comments icon0
A. Rate

B. Feasibility

C. Both A. & B.

D. Neither A. nor B.

30. Variables affecting the rate of homogeneous reactions are___________________?
comments icon0
A. Pressure, temperature and composition

B. Pressure and composition only

C. Pressure and temperature only

D. Temperature and composition only

31. If n is the order of reaction, then unit of rate constant is _________________?
comments icon0

A. None of these

B. (Time)-1 (concentration)n 1

C. 1/(time)(concentration)n 1

D. (Time)n 1 (concentration)

32. For identical flow rate and feed composition, X plug flow reactors (PER) in series with a total volume V gives the same conversion as single_______________?
comments icon0

A. CSTR of volume V/X

B. CSTR of volume V

C. PFR of volume V/X

D. PFR of volume V
33. 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_______________________?
comments icon0

A. d(VCA)/dt = -FCA kCA2V

B. d(VCA)/dt = FCAF kCA2V

C. d(VCA)/dt = F (CAF CA) kCA2V

D. d(VCA)/dt = -F (CAF CA) kCA2V

34. The reaction in which one of the products of reaction acts as a catalyst is called a/an ______________ reaction?
comments icon0
A. Autocatalytic

B. Catalytic

C. Photochemical

D. Biochemical

35. Differential method for analysing the kinetic data is used ___________________?
comments icon0

A. When the data are scattered

B. None of these

C. For testing complicated mechanisms

D. When rate expressions are very simple

36. In a CSTR _______________ varies with time ?
comments icon0

A. Reaction rate

B. Concentration

C. Both A. & B.

D. Neither A. nor B.
37. 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)_____________________?
comments icon0

A. CA

B. CA2

C. CA3

D. CA4

38. Half life period of a chemical reaction is_________________?
comments icon0

A. Half of the space time of a reaction

B. The time required to reduce the concentration of the reacting substance to half its initial value

C. None of these

D. Half of the residence time of a reaction

39. The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an _______________ reaction?
comments icon0

A. Parallel

B. Elementary

C. Autokinetic

D. Non-elementary

40. Rate of a gaseous phase reaction is given by the reaction shown in the bellow figure. The unit of rate constant is__________________?
comments icon0

A. atm.(hr)-1

B. (atm)-1

C. (hr)-1

D. (atm)-1.(hr)-1
41. A photochemical reaction is _______________ light?
comments icon0

A. Used to convert heat energy into

B. Accompanied with emission of

C. Catalysed by

D. Initiated by
42. The conversion for a first order liquid phase reaction. A ? B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be_____________________?
comments icon0

A. 60

B. 90

C. 100

D. 75
43. For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction?
comments icon0
A. [CA0/(1 + ?A XA)] (dXA/dt) = k

B. -ln(1 XA) = kt

C. ?A . ln (1 XA) = k . t

D. XA = k . t

44. The E curve for a non-ideal reactor defines the fraction of fluid having age between t and t + dt _____________________?
comments icon0

A. Averaged over the inlet and outlet

B. At the outlet

C. At the inlet

D. In the reactor

45. 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?
comments icon0

A. 390

B. 190

C. 290

D. 490

46. For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the _______________ is the controlling resistance?
comments icon0

A. Chemical reaction

B. Diffusion through ash layer

C. Either A., B. or C.

D. Film diffusion

47. What is the order of a chemical reaction whose rate is deter-mined by the variation of one concentration term only ?
comments icon0
A. First

B. Zero

C. Third

D. Second

48. The reaction A ? B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is __________________?
comments icon0

A. 2

B. 1

C. 0

D. 1.5

49. Fluidised bed reactor is characterized by____________________?
comments icon0

A. Comparatively smaller equipment

B. Uniformity of temperature

C. Absence of continuous catalyst regeneration facility

D. Very small pressure drop

50. In which of the following reactions, the equilibrium will shift to the right, if the total pressure is increased ?
comments icon0

A. H2 + Cl2 ? 2HCl

B. N2 + O2 ? 2NO

C. N2O4 ? 2 NO2

D. H2 + I2 ? 2HI