Chemical Engineering Archives

8001. A catalyst inhibitor

Lessens its selectivity

May be useful for suppressing undesirable side reactions

Is added in small quantity during the catalyst manufacture itself

All of the above

✅ The correct answer is option D.

8002. Enzymes are destroyed, when the

Temperature is very high

Reactant’s concentration is very high

Reactant’s concentration is very low

Reaction rate is independent of the reactant’s concentration

✅ The correct answer is option A.

8003. Holding time for flow reactors is __________ the space time, for constant fluid density

Double

Triple

Equal to

None of these

✅ The correct answer is option C.

8004. Batch process is preferred over continuous process, when the

Product yields and quality can not be achieved in continuous process, because of long residence time

Sales demand of product is not steady

Same equipment can not be used for several processes of the same nature

All of the above

✅ The correct answer is option D.

8005. For a tubular reactor with space time ‘τ’ and residence time ‘θ’, the following statement holds good.

τ and θ are always equal

τ = θ , when the fluid density changes in the reactor

τ = θ , for an isothermic tubular reactor in which the density of the process fluid is constant

τ = θ , for a non-isothermal reactor

✅ The correct answer is option C.

8006. In the reversible reaction of the type, A + B ⇋ AB, in general

Both forward and backward reactions will be exothermic

Neither of the reactions will be en-dothermic

The combination reaction will be exothermic, while the dissociation reaction will be endothermic

The combination reaction will be endothermic, while the dissociation reaction will be exothermic

✅ The correct answer is option C.

8007. The half life period of a first order reaction is given by (where, K = rate constant. )

1.5 K

2.5 K

0.693/K

6.93 K

✅ The correct answer is option C.

8008. The energy of activation of a chemical reaction

Is same as heat of reaction at constant pressure

Is the minimum energy which the molecules must have before the reaction can take place

Varies as fifth power of the temperature

Both B and C

✅ The correct answer is option B.

8009. 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.

Film diffusion

Diffusion through ash layer

Chemical reaction

Either A, B or C

✅ The correct answer is option B.

8010. In an exothermic reaction, the energy of the reacting substances as compared to that of products is

Less

Same

Either A or B, depends on order of reaction

✅ The correct answer is option A.