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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.
| 701. |
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 | |
| 702. |
The performance of a cascade of CSTR's can be improved by adding? |
| A. | A P.F. reactor in series |
| B. | A P.F. reactor in parallel |
| C. | More CSTR's in series |
| D. | More CSTR's in parallel |
| Answer» D. More CSTR's in parallel | |
| 703. |
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. | |
| 704. |
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 | |
| 705. |
Which of the following resistances is not involved in a gas phase catalytic (gas- solid) reaction?? |
| A. | Ash resistance |
| B. | Gas film and pore surface diffusion resistances for reactants |
| C. | Surface phenomenon resistance |
| D. | Gas film and pore surface diffusion resistances for products |
| Answer» B. Gas film and pore surface diffusion resistances for reactants | |
| 706. |
Pick out the wrong statement? |
| A. | For the same conversion, the holding time required in a batch reactor, is always equal to the space time required in a PFR |
| B. | Two mixed reactors of unequal size are available for producing a specified product, formed by a homogenous second order reaction. To achieve maximum production rate, the smaller reactor should be plac |
| C. | Arrehenius equation describing the effect of temperature on rate constant is given by, K = A.e-Ea/RT |
| D. | The mechanism for the decomposition of CH‚ÇÉCHO into CH‚ÇÑ and CO in presence of I‚ÇÇ is:CH‚ÇÉCHO +I‚ÇÇ CH‚ÇÉI + HI + CO; slowCH‚ÇÉI + HI CH‚ÇÑ + I‚ÇÇ; fastThen the rate of disappearance |
| Answer» E. | |
| 707. |
Which of the following is the optimum operating condition for an exothermic reversible reaction taking place in a plug-flow reactor?? |
| A. | Temperature should be high in the beginning and decreased towards the end of the reaction |
| B. | Very low temperature should be used throughout the reaction |
| C. | Very high temperature should be used throughout the reaction |
| D. | None of these |
| Answer» B. Very low temperature should be used throughout the reaction | |
| 708. |
The energy of activation of a chemical reaction? |
| A. | Is same as heat of reaction at constant pressure |
| B. | Is the minimum energy which the molecules must have before the reaction can take place |
| C. | Varies as fifth power of the temperature |
| D. | Both B and C |
| Answer» C. Varies as fifth power of the temperature | |
| 709. |
Molecularity of an elementary reaction, P + Q ‚Üí R + S is$ |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 710. |
In the gaseous phase ammonia formation reaction (N‚ÇÇ + 3H‚ÇÇ ‚áã 2NH‚ÇÉ), the value of the equilibrium constant depends on the$ |
| A. | Total pressure of the system |
| B. | Volume of the reactor |
| C. | Temperature |
| D. | Initial concentration of N‚ÇÇ and H‚ÇÇ |
| Answer» D. Initial concentration of N‚Äö√á√á and H‚Äö√á√á | |
| 711. |
The concentration of A in a first order reaction, A ‚Üí 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 | |
| 712. |
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 ≈í√ÆG is no measure of feasibility of a reaction | |
| 713. |
With decrease in temperature, the equilibrium conversion of a reversible endother- mic reaction |
| A. | Decreases |
| B. | Increases |
| C. | Remains unaffected |
| D. | Increases linearly with temperature |
| Answer» B. Increases | |
| 714. |
The effectiveness factor for large value of Thiele modulus (L‚à ö(K/D1)) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm¬≤/second)$ |
| A. | L‚à ö(K/D1) |
| B. | 1/(L‚à ö(K/D1)) |
| C. | 1 |
| D. | ‚à û |
| Answer» C. 1 | |
| 715. |
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 | |
| 716. |
In case of calcination of limestone, CaCO‚ÇÉ CaO + CO‚ÇÇ, the addition of more of CaO will result in __________ in the concentration of CO‚ÇÇ.$ |
| A. | No change |
| B. | Increase |
| C. | Decrease |
| D. | Unpredictable from the data |
| Answer» B. Increase | |
| 717. |
Find a mechanism that is consistent with the rate equation and reaction given below: 2A + B ‚Üí A‚ÇÇB, ( - rA) = k.CA.CB$ |
| A. | A + B ‚áã AB ; AB + A ‚Üí A‚ÇÇB |
| B. | A + B ‚áã AB;AB + A ‚Üí A‚ÇÇB |
| C. | A + A ‚áã AA;AA + B ‚Üí A‚ÇÇB |
| D. | A + A ‚áã AA;AA + B ‚Üí A‚ÇÇB |
| Answer» E. | |
| 718. |
The reaction A ‚Üí B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is$ |
| A. | 0 |
| B. | 1 |
| C. | 1.5 |
| D. | 2 |
| Answer» B. 1 | |
| 719. |
For reactions in parallel viz A ‚Üí P (desired product) and A ‚Üí 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 | |
| 720. |
With the same reaction time, initial concentration and feed rate, the reaction 2A ‚Üí B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be$ |
| A. | Higher in P.F. reactor |
| B. | Higher in CSTR |
| C. | Same in both the reactors |
| D. | Data insufficient; can't be predicted |
| Answer» B. Higher in CSTR | |
| 721. |
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 | |
| 722. |
The percent conversion of ethanol in the reactor is |
| A. | 100 |
| B. | 97.5 |
| C. | 95 |
| D. | 2.5 |
| Answer» B. 97.5 | |
| 723. |
In the hydrodealkylation of toluene to benzene, the following reactions occur:C‚ÇáH‚Çà + H‚ÇÇ ‚Üí C‚ÇÜH‚ÇÜ + CH‚ÇÑ2C‚ÇÜH‚ÇÜ ‚áã C‚ÇÅ‚ÇÇH‚ÇÅ‚ÇÄ + H‚ÇÇToluene and hydrogen are fed to a reactor in a molar ratio 1:5.80% of the toluene gets converted and the selectivity of benzene(defined as moles of benzene formed/moles of toluene converted) is 90%. The fractional conversion of hydrogen is$ |
| A. | 0.16 |
| B. | 0.144 |
| C. | 0.152 |
| D. | 0.136 |
| Answer» C. 0.152 | |
| 724. |
For the gaseous reaction 2A ‚Üí B, where the feed consists of 50 mole % A and 50 mole % inerts, the expansion factor is$ |
| A. | 1 |
| B. | -0.5 |
| C. | -0.25 |
| D. | 0 |
| Answer» D. 0 | |
| 725. |
For the liquid phase parallel reactions:R, rR = K?.CA2; E? = 80 KJ/moleS, rS = K?.CA ; E? = 120 KJ/mole The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at |
| A. | Low temperature in a CSTR |
| B. | High temperature in a CSTR |
| C. | Low temperature in a PFR |
| D. | High temperature in a PFR |
| Answer» E. | |
| 726. |
For an isothermal second order aqueous phase reaction, A ‚Üí 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 | |
| 727. |
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 | |
| 728. |
The rate of the chemical reaction A ‚Üí B doubles as the concentration of A i.e.., CA is doubled. If rate of reaction is proportional to CAn, then what is the value of n for this reaction?# |
| A. | 0.5 |
| B. | 1 |
| C. | 0 |
| D. | 2 |
| Answer» C. 0 | |
| 729. |
The rate of the reaction, X ‚Üí 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 | |
| 730. |
If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the |
| A. | Pressure |
| B. | Temperature |
| C. | Both A & B |
| D. | Neither A nor B |
| Answer» C. Both A & B | |
| 731. |
Half life period of a first order irreversible reaction A ‚Üí B is# |
| A. | K/2 |
| B. | Ln k/2 |
| C. | Ln 2/k |
| D. | Ln 0.5/k |
| Answer» D. Ln 0.5/k | |
| 732. |
For a heterogenous catalytic reaction, A + B ‚Üí C, with equimole feed of A and B, the initial rate - rA0 is invariant with total pressure. The rate controlling step is# |
| A. | Surface Kc/(1 + TS) reaction between absorbed A and B in the gas phase |
| B. | Surface reaction between absorbed A and absorbed B |
| C. | Surface reaction between A in the gas phase and absorbed B |
| D. | Desorption of C |
| Answer» E. | |
| 733. |
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. | 0.30 |
| C. | 0.60 |
| D. | 0.90 |
| Answer» D. 0.90 | |
| 734. |
If helium is introduced in a reactor containing O‚ÇÇ, SO‚ÇÇ and SO‚ÇÉ at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO‚ÇÉ (as per Le Chatlier principle)# |
| A. | Decreases |
| B. | Increases |
| C. | Remains unaltered |
| D. | Changes unpredictably |
| Answer» B. Increases | |
| 735. |
A first order irreversible reaction, A ‚Üí B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors.# |
| A. | Both conversion as well as concentration are same |
| B. | Conversion in both will be the same but concentrations will be different |
| C. | Both the conversion as well as concentrations will be different |
| D. | None of these |
| Answer» C. Both the conversion as well as concentrations will be different | |
| 736. |
6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO‚ÇÇ and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant?# |
| A. | 100% |
| B. | 95% |
| C. | 75% |
| D. | 20% |
| Answer» C. 75% | |
| 737. |
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 (vt/V) |
| C. | Thiele modulus (L‚à ö(k/D1) |
| D. | None of these |
| Answer» E. | |
| 738. |
At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500°K and 400°K is 2, if Arrhenious law is used. What will be this ratio, if transition state theory is used with the same value of E/R?# |
| A. | 1.6 |
| B. | 2 |
| C. | 2.24 |
| D. | 2.5 |
| Answer» E. | |
| 739. |
The irreversible reaction, X ‚Üí Y, is the special case of the reversible reaction, X ‚áã Y, in which the# |
| A. | Equilibrium constant is infinite |
| B. | Fractional conversion of |
| C. | Concentration of |
| D. | All of the above |
| Answer» E. | |
| 740. |
Which of the following will give maximum gas conversion? |
| A. | Fixed bed reactor |
| B. | Fluidised bed reactor |
| C. | Semi-fluidised bed reactor |
| D. | Plug-flow catalytic reactor |
| Answer» D. Plug-flow catalytic reactor | |
| 741. |
The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of E/R is# |
| A. | 8987°K |
| B. | 9210°K |
| C. | 8764°K |
| D. | 8621°K |
| Answer» C. 8764¬¨‚àûK | |
| 742. |
If n = overall order of a chemical reaction. a = initial concentration of reactant. t = time required to complete a definite fraction of the reaction. Then pick out the correct relationship. |
| A. | T ‚Äö√ √π 1/an |
| B. | T ‚Äö√ √π 1/an - 1 |
| C. | T ‚Äö√ √π 1/an + 1 |
| D. | T ‚Äö√ √π an |
| Answer» C. T ‚Äö√ √π 1/an + 1 | |
| 743. |
In the converter of the contact process for the manufacture of H‚ÇÇSO‚ÇÑ the equilibrium conversion of SO‚ÇÇ __________ (i) __________ with increase in temperature and __________ (ii) __________ with increase in the mole ratio of SO‚ÇÇ to air.# |
| A. | (i) increases (ii) decreases |
| B. | (i) decreases (ii) increases |
| C. | (i) increases (ii) increases |
| D. | (i) decreases (ii) decreases |
| Answer» C. (i) increases (ii) increases | |
| 744. |
From collison theory, the reaction rate constant is proportional to |
| A. | Exp(- E/RT) |
| B. | Exp(- E/2RT) |
| C. | ‚à öT |
| D. | Tm.exp(- E/RT) |
| Answer» E. | |
| 745. |
A liquid phase reaction is to be carried out under isothermal conditions. The reaction rate as a function of conversion has been determined experimentally and is shown in the figure given below. What choice of reactor or combination of reactors will require the minimum overall reactor volume, if a conversion of 0.9 is desired ? |
| A. | CSTR followed by a PFR |
| B. | PFR followed by a CSTR |
| C. | CSTR followed by a PFR followed by a CSTR. |
| D. | PFR followed by a CSTR followed by a PFR. |
| Answer» E. | |
| 746. |
Cold shot cooling is only practical when the feed temperature is __________ than the reaction temperature. |
| A. | higher |
| B. | much higher |
| C. | lower |
| D. | much lower |
| Answer» E. | |
| 747. |
A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to |
| A. | lose a proton. |
| B. | gain a proton. |
| C. | lose an electron |
| D. | none of these. |
| Answer» B. gain a proton. | |
| 748. |
For the chemical reaction X Y, it is observed that, on doubling the concentration of 'X', the reaction rate quadruples. If the reaction rate is proportional to Cxn, then what is the value of 'n' ? |
| A. | 4 |
| B. | 43556 |
| C. | 16 |
| D. | 2 |
| Answer» B. 43556 | |
| 749. |
The half life period 't' of a zero order reaction, , is equal to |
| A. | CA0/2K |
| B. | CA0/K |
| C. | 0.693/K |
| D. | 1/K |
| Answer» B. CA0/K | |
| 750. |
In case of unimolecular type elementary reaction, , plug flow reactor as compared to mixed reactor is |
| A. | more |
| B. | same |
| C. | less |
| D. | unpredictable |
| Answer» B. same | |