chemical engineering chemical reaction Mcqs
401. Molecularity of a reaction__________________?
comments icon0

A. Is always equal to the overall order of reaction

B. May not be equal to the order of reaction

C. Cant have a fractional value

D. Both B. and C.
402. Pick out the correct statement?
comments icon0

A. A catalyst initiates a chemical reaction

B. A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction

C. In catalytic reactions, the catalyst reacts with the reactants

D. A catalyst lowers the activation energy of the reacting molecules

403. If helium is introduced in a reactor containing O2, SO2 and SO3 at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO3 (as per Le Chateliers principle)?
comments icon0

A. Increases

B. Remains unaltered

C. Decreases

D. Changes unpredictably

404. Which of the following chemical reactions will be favoured by low pressure ?
comments icon0
A. N2O2 ? 2NO2

B. None of these

C. 2HI ? H2 + I2

D. N2 + O2 ? 2NO

405. An endothermic aqueous phase first order irreversible reaction is carried out in an adiabatic plug flow reactor. The rate of reaction ?
comments icon0

A. Goes through a maximum along the length of the reactor

B. Is maximum at the inlet of the reactor

C. Goes through a minimum along the length of the reactor

D. Is maximum at the exit of the reactor

406. According to Arrhenius equation of temperature dependency of rate constant for an elementary reaction _________________?
comments icon0

A. None of these

B. k ? T e-E/RT

C. k ? ?T

D. k ? e-E/RT
407. In the gaseous phase ammonia formation reaction (N2 + 3H2 ? 2NH3), the value of the equilibrium constant depends on the_________________?
comments icon0

A. Volume of the reactor

B. Temperature

C. Total pressure of the system

D. Initial concentration of N2 and H2

408. From among the following, choose one which is not an exothermic process ?
comments icon0

A. Methanol synthesis

B. Catalytic cracking

C. Ammonia synthesis

D. Oxidation of sulphur

409. During manufacture of H2SO4, the oxidation of SO2 to SO3 by oxygen is an endothermic reaction. The yield of SO3 will be maximised, if the _____________________?
comments icon0

A. Temperature is increased and pressure is reduced

B. Pressure is reduced

C. Temperature is reduced and pressure is increased

D. Temperature is increased

410. Pick out the wrong statement?
comments icon0

A. The ratio of volumes of plug flow reactor to that of mixed reactor is always less than one for identical feed composition, flow rate, conversion and for all positive reaction orders

B. The differential method of analysing kinetic data requires more accurate or larger amounts of data

C. When the reaction rate is independent of temperature, the reaction is said to be of zero order

D. The integral method of analysing kinetic data is used when the data is scattered

411. The ratio of moles of a reactant converted into the desired product to that converted into unwanted product is called_________________?
comments icon0

A. Operational yield

B. Relative yield

C. None of these

D. Selectivity
412. If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to___________________?
comments icon0

A. (E + ED)/2

B. (E + ED) where ED is activation due to diffusion

C. The intrinsic activation energy E

D. ED/2
413. A photochemical reaction is _______________?
comments icon0
A. Initiated by light

B. All A., B. & C.

C. Accompanied with emission of light

D. Catalysed by light

414. The role of a catalyst in a chemical reaction is to change the__________________?
comments icon0

A. Heat of reaction

B. Final products

C. Equilibrium constant

D. Activation energy
415. Sulphuric acid is used as a catalyst in the_______________?
comments icon0

A. Hydrogenation of oils

B. Alkylation of hydrocarbons

C. Gas phase oxidation of SO2 in chamber process

D. None of these

416. Which of the following is not a chemical step in a fluid solid catalytic reaction ?
comments icon0

A. Surface chemical reaction

B. None of these

C. Desorption

D. Adsorption

417. Ionic reactions occur in____________________?
comments icon0

A. Solid state only

B. Any state

C. Solutions

D. Liquid state only

418. The rate of the heterogeneous catalytic reaction A(g) + B(g) ? C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?
comments icon0

A. Surface reaction between A in the gas phase and absorbed B

B. Surface reaction between absorbed A and B in the gas phase

C. Surface reaction between absorbed A and absorbed B

D. Absorption of A

419. Pick the WRONG design guideline for a reactor in which the reactions, A ? R (desired) and A ? S (undesired) are to take place. The ratio of the reaction rates is rR/rS = (k1/k2). CA a-b ?
comments icon0

A. Use batch reactor or plug flow reactor, when a > b

B. Use CSTR with a high conversion, when a > b

C. Use high pressure and eliminate inerts, when a > b

D. Avoid recycle, when a > b
420. In which of the following gaseous phase reversible reactions, the product yield cannot be increased by the application of high pressure ?
comments icon0

A. 2SO2 + O2 ? 2SO3

B. PCl3 + Cl2 ? PCl5

C. N + 3H2 ? 2NH3

D. N2 + O2 ? 2NO
421. The experimentally determined overall order of the reaction, A + B ? C + D, is two. Then the__________________?
comments icon0

A. Reaction is elementary but the molecularity may not be 2

B. Reaction is elementary with a molecularity of 2

C. Molecularity of the reaction is 2, but the reaction may not be elementary

D. Reaction may be elementary with molecularity of 2

422. Pick out the correct statement ?
comments icon0

A. A catalyst speeds up the forward reaction but slows shown the reverse reaction

B. The composition of equilibrium is changed by catalyst

C. Pressure changes do not change the equilibrium concentrations

D. Addition of catalyst changes the equilibrium constant

423. For a first order chemical reaction, the rate constant_________________?
comments icon0
A. Has unit of time-1

B. Changes on changing the concentration units

C. None of these

D. Is not a function of the unit of time

424. When a catalyst increases the rate of forward reaction, the value of rate constant__________________?
comments icon0

A. Remain same

B. Decreases

C. Becomes infinite

D. Increases
425. In a semi-batch reactor __________________?
comments icon0
A. Velocity of reaction can be controlled

B. Mixing takes place in axial direction only

C. Condition similar to plug flow reactor exists

D. Residence time is constant

426. What is the dispersion number for a plug flow reactor ?
comments icon0

A. ?

B. -1

C. 1

D. 0
427. A reactor is generally termed as an autoclave, when it is a_____________________?
comments icon0
A. High pressure batch reactor

B. Atmospheric pressure CSTR

C. Atmospheric pressure tank reactor

D. High pressure tubular reactor

428. Rate constant k and absolute temperature T are related by collision theory (for bimolecular) as______________________?
comments icon0

A. k ? T1.5

B. k ? exp(-E/RT)

C. k ? ?T

D. k ? T

429. There is no correspondence between stoichiometric and the rate equation in case of a/an _____________ reaction?
comments icon0

A. Autocatalytic

B. Non-elementary

C. Multiple

D. Elementary

430. In a chemical reaction, _____________________ are conserved?
comments icon0

A. Ions

B. Masses

C. Atoms

D. Both B. & C.
431. The following half life data are available for the irreversible liquid phase reaction A ? products. The overall order of reaction is __________________?
comments icon0

A. 2

B. 0.5

C. 1.5

D. 1

432. The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate, feed composition and conversion) for zero order reaction is________________?
comments icon0

A. ?

B. > 1

C. 0

D. 1
433. A catalyst is said to be a negative catalyst, if it ___________________?
comments icon0

A. Reduces the value of equilibrium constant

B. Does not initiate the reaction

C. All A., B. and C.

D. Retards the rate of reaction
434. A catalyst______________________?
comments icon0
A. Lowers the activation energy of reacting molecules

B. Is capable of reacting with any one of the reactants

C. Initiates a reaction

D. Cannot be recovered chemically unchanged at the end of a chemical reaction

435. A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For minimum reactor volume, it should be operated such that the temperature along the length ?
comments icon0

A. Increases

B. Is at the highest allowable temperature throughout

C. First increases and then decreases

D. Decreases

436. The conversion in a mixed reactor/accomplishing a reaction A ? 3R is 50% when gaseous reactant A is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is _______________ second?
comments icon0

A. 3

B. 1

C. 2

D. 0.5
437. Rate determining step in a reaction consisting of a number of steps in series is the ______________ step?
comments icon0

A. Fastest

B. Slowest

C. Intermediate

D. Data insufficient; cant be predicted

438. In case of physical adsorption, the heat of adsorption is of the order of _____________ kcal/kg mole?
comments icon0
A. 1000

B. 10000

C. 100

D. 100000

439. A balanced chemical reaction equation conforms to the law of________________?
comments icon0

A. None of these

B. Avogadros hypothesis

C. Gaseous volumes

D. Conservation of mass
440. Which of the following is an autocatalytic reaction ?
comments icon0

A. Ammonia synthesis reaction

B. Photochemical reactions

C. Enzyme fermentation reaction

D. Microbial fermentation reaction
441. A gaseous reactant is introduced in a mixed reactor of 3 litres volume at the rate of 1 litre/second. The space time is ______________ seconds?
comments icon0

A. 1

B. 32

C. 3

D. 3-Jan

442. Radioactive decay follows ______________ order kinetics?
comments icon0

A. Zero

B. Third

C. Second

D. First
443. The eddy diffusivity for a liquid in plug flow must be_________________?
comments icon0

A. ?

B. 0

C. 1

D. Between 0 and 1

444. Reaction rate equation for the bellow figure reaction, If S at is present in large excess, what is the order of this reaction ?
comments icon0

A. Zero

B. Three

C. Two

D. One
445. The catalytic activity of enzymes is due to their capacity to lower the ______________ energy?
comments icon0

A. Potential

B. Kinetic

C. None of these

D. Activation
446. ______________ is the response curve for a step input signal from a reactor ?
comments icon0
A. C-curve

B. S-curve

C. None of these

D. I-curve

447. An autothermal reactor is_________________?
comments icon0

A. Most suitable for a second order reaction

B. Isothermal in nature

C. Completely self-supporting in its thermal energy requirements

D. Most suitable for a reversible reaction

448. For an isothermal second order aqueous phase reaction, A ? B, the ratio of the time required for 90% conversion to the time required for 45% conversion is____________________?
comments icon0

A. 22

B. 2

C. 11

D. 4

449. The half life period of a first order reaction is given by (where, K = rate constant) ?
comments icon0

A. 6.93 K

B. 1.5 K

C. 2.5 K

D. 0.693/K
450. A multiple reaction may be classified as a ________________ reaction?
comments icon0

A. Consecutive or side

B. Mixed

C. All A., B. and C.

D. Parallel or side