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MCQOPTIONS
This section includes 1443 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 801. |
A chemical reaction is of zero order, when the reaction rate is (where, CA = concentration of reactant) |
| A. | ‚àù CA. |
| B. | ‚àù 1/CA. |
| C. | independent of temperature. |
| D. | none of these. |
| Answer» E. | |
| 802. |
For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to l/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times. |
| A. | 8 |
| B. | 16 |
| C. | 43678 |
| D. | 42370 |
| Answer» C. 43678 | |
| 803. |
In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation. |
| A. | adiabatic |
| B. | isothermal |
| C. | non-adiabatic |
| D. | none of these. |
| Answer» D. none of these. | |
| 804. |
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 |
| A. | 2 |
| B. | 4 |
| C. | 11 |
| D. | 22 |
| Answer» D. 22 | |
| 805. |
The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line ? |
| A. | XA Vs . τ |
| B. | XA Vs ln τ |
| C. | XA/(1 - XA)Vs τ |
| D. | XA(1 - XA)Vs τ |
| Answer» B. XA Vs ln œÑ | |
| 806. |
Rate determining step in a reaction consisting of a number of steps in series is the __________ step. |
| A. | fastest |
| B. | slowest |
| C. | intermediate |
| D. | data insufficient; can't be predicted |
| Answer» C. intermediate | |
| 807. |
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 |
| A. | 1 |
| B. | >1 |
| C. | ‚àû |
| D. | ‚â•1 |
| Answer» D. ‚â•1 | |
| 808. |
In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled, then the equilibrium constant will |
| A. | remain the same |
| B. | be halved |
| C. | also be. doubled |
| D. | become one fourth |
| Answer» B. be halved | |
| 809. |
There is no correspondence between stoichiometry and the rate equation in case of a/an __________ reaction. |
| A. | elementary |
| B. | multiple |
| C. | autocatalytic |
| D. | non-elementary |
| Answer» E. | |
| 810. |
Find a mechanism that is consistent with the rate equation and reaction given below:2A + B A2B, ( - rA) = k.CA.CB |
| A. | A + B AB ; AB + A A2B |
| B. | A + B AB;AB + A A2B |
| C. | A + A AA;AA + B A2B |
| D. | A + A AA;AA + B A2B |
| Answer» E. | |
| 811. |
Transition state theory relates the above quantities as |
| A. | k ‚àù e-E/RT |
| B. | k ‚àù T.eE/RT |
| C. | k ‚àù T |
| D. | k ‚àù T1.5 |
| Answer» C. k ‚àù T | |
| 812. |
The rate of an autocatalytic reaction, , is given by -rA = k . CA . CB. In this case, the |
| A. | plot of - rA Vs CA is a straight line with slope k. |
| B. | plot of - rA Vs CA is a hyperbola. |
| C. | rate of disappearance of reactant A is maximum, where CA = CB |
| D. | both 'b' & 'c' |
| Answer» E. | |
| 813. |
Half life period of decomposition of a liquid 'A' by irreversible first order reaction is 12 minutes. The time required for 75% conversion of 'A' is __________ minutes. |
| A. | 18 |
| B. | 24 |
| C. | 6 |
| D. | 12 |
| Answer» C. 6 | |
| 814. |
Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in |
| A. | blood |
| B. | saliva |
| C. | intestine |
| D. | gland |
| Answer» C. intestine | |
| 815. |
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 |
| A. | be more in CSTR than in PFR. |
| B. | be more in PFR than in CSTR. |
| C. | be same in both cases. |
| D. | depend on the temperature. |
| Answer» C. be same in both cases. | |
| 816. |
If in the gaseous phase reaction, N2O4 2NO2, x is the part of N2O4 which dissociates, then the number of molecules at equilibrium will be |
| A. | (1 + x) |
| B. | (1 - x) |
| C. | (1 + x)2 |
| D. | (1 - x)2 |
| Answer» B. (1 - x) | |
| 817. |
The vessel dispersion number (D/μL) for plug flow is$ |
| A. | 0 |
| B. | 500 |
| C. | 750 |
| D. | ‚àû |
| Answer» B. 500 | |
| 818. |
Following isothermal kinetic data are obtained in a basket type of mixed flow reactor for a porous catalyst. Determine the role of pore diffusion and external mass transfer processes. |
| A. | Strong pore diffusion control and mass transfer not controlling. |
| B. | Both pore diffusion and mass transfer not controlling. |
| C. | Both pore diffusion and mass transfer controlling. |
| D. | Mass transfer controlling. |
| Answer» B. Both pore diffusion and mass transfer not controlling. | |
| 819. |
For a __________ order chemical reaction, , the half life period is independent of the initial concentration of the reactant A. |
| A. | zero |
| B. | first |
| C. | second |
| D. | third |
| Answer» C. second | |
| 820. |
The rate of the reaction, X Y, quadruples when the concentration of 'X' is doubled. The rate expression for the reaction is, r = K Cxn, the value of 'n' in this case will be |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» D. 3 | |
| 821. |
For the liquid phase zero order irreversible reaction A B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1min-1 . What will be the conversion for a PFR with a space velocity of 0.2 min-1? Assume that all the other operating conditions are the same for CSTR and PFR. |
| A. | 0.15 |
| B. | 0.3 |
| C. | 0.6 |
| D. | 0.9 |
| Answer» D. 0.9 | |
| 822. |
Molecularity of an elementary reaction, P + Q R + S is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 823. |
The knowledge of initial concentration and rate constant is necessary to determine the half life time of a reaction of __________ order. |
| A. | zero |
| B. | first |
| C. | second |
| D. | none of these |
| Answer» D. none of these | |
| 824. |
A first order reaction A B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A at the centre of the pellet is much less than at the external surface, the process is limited by |
| A. | diffusion within the pellet. |
| B. | reaction. |
| C. | external mass transfer. |
| D. | none of the above. |
| Answer» B. reaction. | |
| 825. |
Which of the following is not a chemical step in a fluid solid catalytic reaction ? |
| A. | Surface chemical reaction |
| B. | Adsorption |
| C. | Desorption |
| D. | None of these |
| Answer» E. | |
| 826. |
Calcination reaction of limestone (CaCO3 CaO + CO2) goes to completion in the rotary kiln, because |
| A. | CaO is not dissociated. |
| B. | CO2 escapes continuously. |
| C. | of high calcination temperature. |
| D. | CaO is more stable than CaCO3. |
| Answer» C. of high calcination temperature. | |
| 827. |
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. |
| A. | 1 |
| B. | 3 |
| C. | 43525 |
| D. | 32 |
| Answer» C. 43525 | |
| 828. |
A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction. |
| A. | less than |
| B. | equal to |
| C. | more than |
| D. | equal to or more than |
| Answer» E. | |
| 829. |
For a first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the |
| A. | catalyst size is reduced or the catalyst diffusivity is reduced. |
| B. | catalyst size is reduced or the catalyst diffusivity is increased. |
| C. | catalyst size is increased or the catalyst diffusivity is reduced. |
| D. | catalyst size is increased or the catalyst diffusivity is increased. |
| Answer» C. catalyst size is increased or the catalyst diffusivity is reduced. | |
| 830. |
For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a __________ reactor. |
| A. | stirred tank |
| B. | tubular flow |
| C. | batch |
| D. | fixed bed |
| Answer» B. tubular flow | |
| 831. |
In the converter of the contact process for the manufacture of H2SO4 the equilibrium conversion of SO2 __________ (A) __________ with increase in temperature and __________ (B) __________ with increase in the mole ratio of SO2 to air. |
| A. | (A) increases (B) decreases |
| B. | (A) decreases (B) increases |
| C. | (A) increases (B) increases |
| D. | (A) decreases (B) decreases |
| Answer» C. (A) increases (B) increases | |
| 832. |
Helium-mercury method can be used to determine the __________ of the catalyst particle. |
| A. | pore volume |
| B. | solid density |
| C. | porosity |
| D. | all (a), (b), & (c). |
| Answer» E. | |
| 833. |
Which of the following is not a dimension-less group used in catalysis ? (where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2/sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3/sec . V = volume, cm3.) |
| A. | Reactor dispersion number (D/vL) |
| B. | Reduced time |
| C. | Thiele modulus |
| D. | None of these |
| Answer» E. | |
| 834. |
A chemical reaction, A 3B, is conducted in a constant pressure vessel. Starting with pure A, the volume of the reaction mixture increases 3 times in 6 minutes. The fractional conversion is |
| A. | 0.33 |
| B. | 0.5 |
| C. | 1 |
| D. | data insufficient, can't be predicted |
| Answer» D. data insufficient, can't be predicted | |
| 835. |
What is the dispersion number for a plug flow reactor ? |
| A. | 0 |
| B. | ‚àû |
| C. | 1 |
| D. | -1 |
| Answer» B. ‚àû | |
| 836. |
For a tubular reactor with space time 'τ' and residence time 'θ', the following statement holds good.$ |
| A. | τ and θ are always equal. |
| B. | τ = θ , when the fluid density changes in the reactor. |
| C. | τ = θ , for an isothermic tubular reactor in which the density of the process fluid is constant. |
| D. | τ = θ , for a non-isothermal reactor. |
| Answer» D. œÑ = Œ∏ , for a non-isothermal reactor. | |
| 837. |
A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction. |
| A. | less than |
| B. | equal to |
| C. | more than |
| D. | equal to or more than |
| Answer» E. | |
| 838. |
When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ coloumn. |
| A. | packed |
| B. | spray |
| C. | tray |
| D. | bubble |
| Answer» E. | |
| 839. |
Which of the following holds good for an elementary reaction, ? |
| A. | The rate of disappearance of 'Y' is equal to the rate of appearance of 'Z'. |
| B. | The rate of disappearance of 'Y' is equal to the rate of disappearance of 'X'. |
| C. | Three times the rate of disappearance of 'X' is equal to the rate of appearance of 'Z'. |
| D. | The rate of disappearance of 'X' is equal to the rate of appearance of 'Z'. |
| Answer» D. The rate of disappearance of 'X' is equal to the rate of appearance of 'Z'. | |
| 840. |
B.E.T. method can be used to determine the __________ of a porous catalyst. |
| A. | solid density |
| B. | pore volume |
| C. | surface area |
| D. | all (a), (b) and (c) |
| Answer» D. all (a), (b) and (c) | |
| 841. |
A second order reaction of the form A + B C is called a pseudo-first order reaction, when |
| A. | CA0 = CB0 |
| B. | CA0 > CB0 |
| C. | CB0 > CA0 |
| D. | CB0 ‚â• CB0 |
| Answer» E. | |
| 842. |
A typical example of an exothermic reversible reaction conducted at high pressure in industry is |
| A. | dehydration of ethanol. |
| B. | methanol synthesis. |
| C. | reformation of methane. |
| D. | polymerisation of ethylene. |
| Answer» B. methanol synthesis. | |
| 843. |
To maximise the formation of R in the simultaneous reactionA + B R , rR = 2CA0.5.CB2 A + B S , rS = 1.5 CA . CBWe should have |
| A. | low CA, low CB |
| B. | low CA, high CB |
| C. | high CA, low CB |
| D. | high CA, high CB |
| Answer» C. high CA, low CB | |
| 844. |
The equilibrium constant for the reversible reaction, , is affected by the |
| A. | temperature of the system. |
| B. | presence or absence of inerts. |
| C. | pressure of the system. |
| D. | kinetics of the reaction. |
| Answer» D. kinetics of the reaction. | |
| 845. |
Which of the following is not endothermic in nature ? |
| A. | Combustion of sulphur. |
| B. | Gasification of carbon. |
| C. | Thermal cracking of fuel oil. |
| D. | Steam reforming of naphtha. |
| Answer» B. Gasification of carbon. | |
| 846. |
An elementary liquid phase decomposition reaction is to be carried out in a CSTR. The design equation is |
| A. | kτ = XA/(1 - XA) |
| B. | kτ = XA(1 + XA)/(1 + XA) |
| C. | kτ = XA/(1 - XA)2 |
| Answer» B. kœÑ = XA(1 + XA)/(1 + XA) | |
| 847. |
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. |
| A. | decrease |
| B. | increase |
| C. | no change |
| D. | either (a) or (b), depends on the type of reaction |
| Answer» D. either (a) or (b), depends on the type of reaction | |
| 848. |
Rate constant 'k' and absolute temperature 'T' are related by collision theory (for bimolecular) as |
| A. | k ‚àù T1.5 |
| B. | k ‚àù exp(-E/RT) |
| C. | k ‚àù T |
| D. | k ‚àù T |
| Answer» D. k ‚àù T | |
| 849. |
The exit age distribution of a fluid leaving a vessel (denoted by E) is used to study the extent of non-ideal flow in the vessel. The value of is |
| A. | 0 |
| B. | 1 |
| C. | ‚àû |
| D. | 2π |
| Answer» C. ‚àû | |
| 850. |
In a chemical reaction, repesented by, , 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 = contentration of the reactant) |
| A. | CA |
| B. | CA2 |
| C. | CA3 |
| D. | CA4 |
| Answer» C. CA3 | |