21. A photochemical reaction is __________ light.
Initiated by
Accompanied with emission of
Catalysed by
Used to convert heat energy into
✅ The correct answer is option A.
Chemical Reaction Engineering MCQs
22. Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in __________ in conversion.
Decrease
Increase
No change
Either A or B, depends on the type of reaction
✅ The correct answer is option C.
24. A reactor is generally termed as an autoclave, when it is a
High pressure batch reactor
Atmospheric pressure tank reactor
High pressure tubular reactor
Atmospheric pressure CSTR
✅ The correct answer is option A.
25. Mean residence time is equal to the space time, when
The feed rate is measured at temperature and pressure in the reactor
The temperature, pressure and the density of reaction mixture remains constant throughout the reactor
There is no change in number of moles in gaseous reaction
All of the above
✅ The correct answer is option D.
26. Threshold energy in a reaction is equal to the
Activation energy
Normal energy of reactants
Sum of A & B
Neither A nor B
✅ The correct answer is option C.
27. An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will
Be more in CSTR than in PFR
Be more in PFR than in CSTR
Be same in both cases
Depend on the temperature
✅ The correct answer is option B.
28. In an exothermic chemical reaction, the reactants compared to the products have
Higher temperature
More energy
Less energy
Same energy
✅ The correct answer is option B.
29. If the rate of a chemical reaction becomes slower at a given temperature, then the
Initial concentration of the reactants remains constant
Free energy of activation is lower
Entropy changes
Free energy of activation is higher
✅ The correct answer is option D.
30. From among the following, choose one which is not an exothermic process.
Methanol synthesis
Catalytic cracking
Ammonia synthesis
Oxidation of sulphur
✅ The correct answer is option B.