MCQOPTIONS
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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.
| 751. |
In which of the following gaseous phase reversible reactions, the product yield can not be increased by the application of high pressure ? |
| A. | N2 + O2 2NO |
| B. | PCl3 + Cl2 PCl5 |
| C. | N + 3H2 2NH3 |
| D. | 2SO2 + O2 2SO3 |
| Answer» B. PCl3 + Cl2 PCl5 | |
| 752. |
According to Arhenious equation of temperature dependency of rate constant for an elementary reaction |
| A. | k ‚àù T |
| B. | k ‚àù e-E/RT |
| C. | k ‚àù T e-E/RT |
| D. | none of these |
| Answer» C. k ‚àù T e-E/RT | |
| 753. |
A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: CA0= 5 kmole/m3 ; XA = 0.5; Feed temperature = reactor temperature = 40°C. Rate constant at 40°C = 1 min-1 ; (ΔH) = - 40kJ/mole; ρ = 1000kg/m3 CP = 4 J/gm.°C ; q = 10-3 m3/min (ρ and CP are same for the reactant and product streams). The amount of heat to be removed is$ |
| A. | 2/3 kW |
| B. | 1kW |
| C. | 5/3 kW |
| D. | 4kW |
| Answer» D. 4kW | |
| 754. |
The value of 'n' for a chemical reaction A B, whose reaction rate is CAn, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled. |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» E. | |
| 755. |
The response curve for a step input signal from a reactor is called C-curve. The variance of C-curve in a 'tanks in series model' comprising of 'm' tanks is equal to |
| A. | m |
| B. | 1/m |
| C. | m |
| D. | m2 |
| Answer» C. m | |
| 756. |
What is the Thiele modulus of the solid catalysed first order reaction, , if the pore diffusion offers negligible resistance to reaction ? |
| A. | < 5 |
| B. | < 0.5 |
| C. | > 1 |
| D. | 5 |
| Answer» C. > 1 | |
| 757. |
For the reaction, A + B 2B + C, |
| A. | rA = rB |
| B. | rA = -rB |
| C. | rA = 2rB |
| D. | rA = rB/2 |
| Answer» C. rA = 2rB | |
| 758. |
Study of chemical kinetics is the easiest in the case of __________ reactions. |
| A. | irreversible |
| B. | reversible |
| C. | surface |
| D. | side |
| Answer» B. reversible | |
| 759. |
Half life period of a chemical reaction is proportional to CA0-1 , if the reaction is of __________ order. |
| A. | first |
| B. | zero |
| C. | second |
| D. | third |
| Answer» D. third | |
| 760. |
For a __________ order reaction, the units of rate constant and rate of reaction are the same. |
| A. | zero |
| B. | first |
| C. | second |
| D. | fractional |
| Answer» B. first | |
| 761. |
On application of pressure to the equilibrium system, ice water ; which of the following phenomenon will occur ? |
| A. | Water will evaporate |
| B. | Equilibrium will not be attained |
| C. | More ice will be formed |
| D. | More water will be formed. |
| Answer» E. | |
| 762. |
In a/an __________ vessel, the fluid enters and leaves following plug flow. |
| A. | open |
| B. | closed |
| C. | open-closed |
| D. | close-opened |
| Answer» C. open-closed | |
| 763. |
'n' number of plug flow reactors (P.F.R) in series with a total volume 'V' gives the same conversion as one P.F.R. of volume |
| A. | V/n |
| B. | V |
| C. | V.n |
| D. | 1/V |
| Answer» C. V.n | |
| 764. |
For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant |
| A. | is independent of pressure. |
| B. | increases with pressure. |
| C. | decreases with pressure. |
| D. | increases /decreases with pressure depending on the stoichiometric co-efficients of the reaction. |
| Answer» C. decreases with pressure. | |
| 765. |
The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the$ |
| A. | increased temperature reduces the activation energy. |
| B. | fraction of molecules having threshold energy increases. |
| C. | collision frequency increases. |
| D. | value of threshold energy decreases. |
| Answer» C. collision frequency increases. | |
| 766. |
The equilibrium constant of chemical reaction __________ in the presence of catalyst. |
| A. | increases |
| B. | decreases |
| C. | remains unaffected |
| D. | can either increase or decrease (depends on the type of catalyst) |
| Answer» D. can either increase or decrease (depends on the type of catalyst) | |
| 767. |
An exothermic reaction takes place in an adiabatic reactor. The product temperature __________ reactor feed temperature. |
| A. | is always equal to |
| B. | is always greater than |
| C. | is always less than |
| D. | may be greater or less than |
| Answer» C. is always less than | |
| 768. |
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 |
| A. | ‚àû |
| B. | 0 |
| C. | 1 |
| D. | > 1 |
| Answer» D. > 1 | |
| 769. |
With increase in the space time of an irreversible isothermal reaction being carried out in a P.F. reactor, the conversion will |
| A. | increase |
| B. | decrease |
| C. | remain same |
| D. | data in insufficient; can't be predicted |
| Answer» B. decrease | |
| 770. |
Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature ? |
| A. | Time |
| B. | Useful volume of the tank |
| C. | Diameter of the reactor |
| D. | None of these |
| Answer» B. Useful volume of the tank | |
| 771. |
The experimentally determined overall order of the reaction, A + B C + D, is two. Then the |
| A. | reaction is elementary with a molecularity of 2. |
| B. | molecularity of the reaction is 2, but the reaction may not be elementary. |
| C. | reaction may be elementary with molecularity of 2. |
| D. | reaction is elementary but the molecularity may not be 2. |
| Answer» B. molecularity of the reaction is 2, but the reaction may not be elementary. | |
| 772. |
Promoter. |
| A. | initiates a chemical reaction and is a catalyst by itself. |
| B. | atlers the position of equilibrium in a reversible reaction. |
| C. | increases the number of active centres by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals. |
| D. | all (a), (b) and (c). |
| Answer» D. all (a), (b) and (c). | |
| 773. |
If ΔG (free energy change) for a chemical reaction is very large and negative, then the reaction is$ |
| A. | not feasible. |
| B. | just feasible. |
| C. | very much feasible. |
| D. | unpredictable as ΔG is no measure of feasibility of a reaction. |
| Answer» D. unpredictable as ŒîG is no measure of feasibility of a reaction. | |
| 774. |
When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only __________ the true value. |
| A. | twice |
| B. | half |
| C. | equal |
| D. | none of these |
| Answer» C. equal | |
| 775. |
Which of the following is used for calcination of limestone and dolomite in industrial practice ? |
| A. | Fluidised bed reactor |
| B. | Moving bed reactor |
| C. | Fixed bed reactor |
| D. | None of these |
| Answer» C. Fixed bed reactor | |
| 776. |
Consider the 'n' th order irreversible liquid phase reaction A B. Which one of the following plots involving half life of the reaction (t1/2) and the initial reactant concentration (CA0) gives a straight line plot ? |
| A. | CA0 Vs t1/2 |
| B. | ln CA0 Vs t1/2 |
| C. | CA0 Vs ln t1/2 |
| D. | ln CA0 Vs ln t1/2 |
| Answer» D. ln CA0 Vs ln t1/2 | |
| 777. |
Overall rate of reaction in a heterogenous 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. |
| A. | proportional to |
| B. | independent of |
| C. | inversely proportional to |
| D. | proportional to the square of |
| Answer» B. independent of | |
| 778. |
Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about __________ minutes. |
| A. | 3 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» C. 6 | |
| 779. |
The rate equation for the reaction represented by, is given by - rx = K1 . Cx/(1 + K2 Cx). At high value of Cx (i.e.., K2Cx > > 1), the order of the reaction and the rate constant are respectively |
| A. | zero order & K1/K2 |
| B. | zero order & K1 |
| C. | first order & K1 |
| D. | first order & K1/K2 |
| Answer» B. zero order & K1 | |
| 780. |
Brunaur, Emmet and Teller (BET) equation is used to determine the specific surface area of a porous particle but not the pore volume & the porosity of the catalyst bed. Which of the following postulates is not used to derive BET equation ? |
| A. | Langmuir's assumption applies to every adsorbed layer. |
| B. | There is no dynamic equilibrium between successive layer. |
| C. | The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer (except the first one) is involved in each of the evaporation process. |
| D. | none of these. |
| Answer» C. The adsorbed layer may be polymolecular in thickness and the heat of adsorption in each layer (except the first one) is involved in each of the evaporation process. | |
| 781. |
The rate of the heterogenous 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 |
| A. | absorption of A. |
| B. | surface reaction between absorbed A and absorbed B. |
| C. | surface reaction between absorbed A and B in the gas phase. |
| D. | surface reaction between A in the gas phase and absorbed B. |
| Answer» D. surface reaction between A in the gas phase and absorbed B. | |
| 782. |
In an exothermic reaction, the energy of the reacting substances as compared to that of products is |
| A. | more |
| B. | less |
| C. | same |
| D. | either (a) or (b), depends on order of reaction. |
| Answer» B. less | |
| 783. |
Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature? |
| A. | Pore diffusion |
| B. | Film diffusion |
| C. | Ash layer diffusion |
| D. | Chemical reaction |
| Answer» C. Ash layer diffusion | |
| 784. |
The units of frequency factor in Arhenious equation |
| A. | are the same as those of the rate constant. |
| B. | depend on the order of the reaction. |
| C. | depend on temperature, pressure etc. of the reaction. |
| D. | are cycles per unit time. |
| Answer» B. depend on the order of the reaction. | |
| 785. |
The rate expression for a heterogenous catalytic reaction is given by, - rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A)$ |
| A. | E |
| B. | E + ΔHA |
| C. | E + ΔHA - ΔHR) |
| D. | ΔHA + ΔHR |
| Answer» D. ŒîHA + ŒîHR | |
| 786. |
A first order reaction is to be treated in a series of two mixed reactors. The total volume of the two reactors is minimum, when the reactors are |
| A. | equal in size. |
| B. | of different sizes. |
| C. | of such size that the ratio of their volumes is < 5. |
| D. | none of these. |
| Answer» B. of different sizes. | |
| 787. |
A first order homogeneous reaction of the type X Y Z (consecutive reaction) is carried out in a CSTR. Which of the following curves respectively show the variation of the concentration of X, Y and Z with time? |
| A. | I, II, III |
| B. | III, II, I |
| C. | III, I, II |
| D. | II, III, i |
| Answer» C. III, I, II | |
| 788. |
The most suitable reactor for carrying out an auto-thermal reaction is a |
| A. | batch reactor |
| B. | CSTR |
| C. | semi-batch reactor |
| D. | plug-flow reactor |
| Answer» C. semi-batch reactor | |
| 789. |
Which of the following is not a unit of reaction rate ? |
| A. | Moles for med/(surface of catalyst) (time) |
| B. | Moles formed/volume of reactor) (time) |
| C. | Mole formed/volume of catalyst) (time) |
| D. | None of these |
| Answer» E. | |
| 790. |
In case of the irreversible unimolecular type, first order reaction, the fractional conversion at any time for constant volume system as compared to variable volume system is |
| A. | more |
| B. | less |
| C. | same |
| D. | either (a) or (b), depends on other factors |
| Answer» D. either (a) or (b), depends on other factors | |
| 791. |
The temperature dependence of reaction rate constant (K) by Arhenius law is given by |
| A. | K α e-E/RT |
| B. | K α eE/RT |
| C. | K α T . e-E/RT |
| D. | K α T . e-E/RT |
| Answer» B. K Œ± eE/RT | |
| 792. |
For reactions in parallel viz A P (desired product) and A Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a |
| A. | batch reactor is preferred over a single CSTR for high yield. |
| B. | tubular reactor is preferred over a single CSTR for high yield. |
| C. | both (a) and (b). |
| D. | single CSTR is the most suitable. |
| Answer» D. single CSTR is the most suitable. | |
| 793. |
The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are |
| A. | 2 & 1 |
| B. | 11 & 2 |
| C. | 2 && 2 |
| D. | 1 & 1 |
| Answer» B. 11 & 2 | |
| 794. |
Transition state theory gives the rate constant as |
| A. | K α e-E/RT |
| B. | K α eE/RT |
| C. | K α T . e-E/RT |
| D. | K α T . e-E/RT |
| Answer» D. K Œ± T . e-E/RT | |
| 795. |
The concentration of A in a first order reaction, A B, decreases |
| A. | linearly with time. |
| B. | exponentially with time. |
| C. | very abruptly towards the end of the reaction. |
| D. | logarithmically with time. |
| Answer» C. very abruptly towards the end of the reaction. | |
| 796. |
The rate of forward reaction, at chemical equilibrium is____the rate of backward reaction. |
| A. | more than |
| B. | less than |
| C. | equal to |
| D. | either (b) or (c) |
| Answer» D. either (b) or (c) | |
| 797. |
What is the value of 'n' if the reaction rate of the chemical reaction A B, is proportional to CAn and it is found that the reaction rate triples, when the concentration of 'A' is increased 9 times ? |
| A. | 43497 |
| B. | 43525 |
| C. | 43709 |
| D. | 3 |
| Answer» B. 43525 | |
| 798. |
An isothermal irreversible reaction is being carried out in an ideal tubular flow reactor. The conversion in this case will __________ with decrease in space time. |
| A. | increase |
| B. | increase exponentially |
| C. | decrease |
| D. | remain unchanged |
| Answer» D. remain unchanged | |
| 799. |
The catalytic converter for conversion of SO2 to SO3 by contact process should have a feed with SO2 content between |
| A. | 2-5% |
| B. | 7-10% |
| C. | 12-15% |
| D. | 20-25% |
| Answer» C. 12-15% | |
| 800. |
The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an __________ reaction. |
| A. | elementary |
| B. | non-elementary |
| C. | parallel |
| D. | autokinetic |
| Answer» B. non-elementary | |