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.
| 1051. |
For the same residence time, which one will give the maximum conversion ? |
| A. | Single stirred tank (v = 5 litres). |
| B. | Two stirred tank (each of 2.5 litres) in series. |
| C. | Stirred tank followed by tubular flow reactor (each of 2.5 litres). |
| D. | Single tubular flow reactor (v = 5 litres). |
| Answer» E. | |
| 1052. |
In case of physical adsorption, the heat of adsorption is of the order of __________ kcal/kg.mole. |
| A. | 100 |
| B. | 1000 |
| C. | 10000 |
| D. | 100000 |
| Answer» C. 10000 | |
| 1053. |
When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is |
| A. | > 1 |
| B. | < 1 |
| C. | 1 |
| D. | 0 |
| Answer» D. 0 | |
| 1054. |
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. | |
| 1055. |
The catalytic activity of enzymes is due to their capacity to lower the __________ energy. |
| A. | Activation |
| B. | Potential |
| C. | Kinetic |
| D. | None of these |
| Answer» B. Potential | |
| 1056. |
Considering the endothermic dissociation of CaCO3 in a closed vessel (CaCO3 ⇌ CaO + CO2), the pressure of CO2 increases, if |
| A. | A catalyst is added |
| B. | The temperature is increased |
| C. | An inert gas is pumped keeping the temperature constant |
| D. | None of these |
| Answer» C. An inert gas is pumped keeping the temperature constant | |
| 1057. |
In case of __________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds. |
| A. | Catalytic |
| B. | Parallel |
| C. | Series |
| D. | Auto catalytic |
| Answer» E. | |
| 1058. |
Thermodynamic equilibrium constant in a system is affected by |
| A. | Inerts |
| B. | Pressure |
| C. | Temperature |
| D. | All (A), (B) & (C) |
| Answer» D. All (A), (B) & (C) | |
| 1059. |
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. | ∞ |
| B. | 0 |
| C. | 1 |
| D. | > 1 |
| Answer» D. > 1 | |
| 1060. |
Sum of the powers of the concentration terms in the rate equation is called the __________ of the reaction. |
| A. | Order |
| B. | Overall order |
| C. | Molecularity |
| D. | None of these |
| Answer» C. Molecularity | |
| 1061. |
A catalyst in a chemical reaction __________ free energy change in the reaction |
| A. | Increases |
| B. | Decreases |
| C. | Either (A) or (B); depends on the type of catalyst |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 1062. |
Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is a function of reaction temperature. In a chemical reaction, the time required to reduce the concentration of reactant from 100 gm moles/litre to 50 gm moles/litre is same as that required to reduce it from 2 gm moles/litre to 1 gm mole/litre in the same volume. Then the order of this reaction is: |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» C. 2 | |
| 1063. |
Which of the following is the most suitable for isothermal operation? |
| A. | Batch reactor |
| B. | Back-mix reactor |
| C. | Plug-flow reactor |
| D. | Fixed bed reactor |
| Answer» C. Plug-flow reactor | |
| 1064. |
The units of frequency factor in Arrhenius 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 | |
| 1065. |
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 | |
| 1066. |
The rate constant of a first order reaction depends on the |
| A. | Concentration of the reactant |
| B. | Temperature |
| C. | Concentration of the product |
| D. | Time |
| Answer» C. Concentration of the product | |
| 1067. |
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) | |
| 1068. |
The catalyst in a second order reversible reaction increases the rate of the forward reaction |
| A. | And decreases that of backward reaction |
| B. | And backward reaction equally |
| C. | Only |
| D. | To a greater extent than that of the backward reaction |
| Answer» C. Only | |
| 1069. |
For a fluidised bed reactor, the most suitable/relevant model is a __________ model. |
| A. | Tank in series |
| B. | Bubbling bed |
| C. | Plug flow |
| D. | None of these |
| Answer» C. Plug flow | |
| 1070. |
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) | |
| 1071. |
For a first order chemical reaction, the rate constant |
| A. | Changes on changing the concentration units |
| B. | Is not a function of the unit of time |
| C. | Has unit of time-1 |
| D. | None of these |
| Answer» D. None of these | |
| 1072. |
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 | |
| 1073. |
_________ is the controlling step in a highly temperature sensitive fluid-solid non-catalytic reaction. |
| A. | Gas film diffusion |
| B. | Ash diffusion |
| C. | Chemical reaction |
| D. | None of these |
| Answer» D. None of these | |
| 1074. |
Reverse reaction in a chemical equilibrium is favoured by the |
| A. | Removal of one of the products regularly |
| B. | Increase in the concentration of one of the products |
| C. | Increase in the concentration of one of the reactants |
| D. | None of these |
| Answer» C. Increase in the concentration of one of the reactants | |
| 1075. |
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; cant be predicted |
| Answer» C. Intermediate | |
| 1076. |
With increase in temperature, the equilibrium __________ rises in case of endothermic reaction. |
| A. | Constant |
| B. | Conversion |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» C. Both (A) & (B) | |
| 1077. |
Catalyst carriers |
| A. | Have very high selectivity |
| B. | Increase the activity of a catalyst |
| C. | Provide large surface area with a small amount of active material |
| D. | Inhibit catalyst poisoning |
| Answer» D. Inhibit catalyst poisoning | |
| 1078. |
What is the unit of the rate constant in a chemical reaction in which 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on? |
| A. | Litre/mole.second |
| B. | Moles/litre.second |
| C. | Litre/mole |
| D. | Litre/second |
| Answer» B. Moles/litre.second | |
| 1079. |
When a catalyst increases the rate of forward reaction, the value of rate constant |
| A. | Increases |
| B. | Decreases |
| C. | Remain same |
| D. | Becomes infinite |
| Answer» B. Decreases | |
| 1080. |
Which of the following is an autocatalytic reaction? |
| A. | Photochemical reactions |
| B. | Microbial fermentation reaction |
| C. | Enzyme fermentation reaction |
| D. | Ammonia synthesis reaction |
| Answer» C. Enzyme fermentation reaction | |
| 1081. |
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 | |
| 1082. |
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 | |
| 1083. |
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. | |
| 1084. |
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 |
| A. | Temperature is increased |
| B. | Pressure is reduced |
| C. | Temperature is increased and pressure is reduced |
| D. | Temperature is reduced and pressure is increased |
| Answer» E. | |
| 1085. |
Effective diffusivity (DE) in a catalyst pellet is related to molecular diffusivity (DN) and Knudsen diffusivity (DK) as |
| A. | DE = DM + DK |
| B. | 1/DE = 1/DN + DK |
| C. | DE = DM . DE |
| D. | DE = DN/DE |
| Answer» C. DE = DM . DE | |
| 1086. |
From Arrhenius law, a plot of loge K versus 1/T gives a straight line with a slope of (-E/R). The unit of E/R is |
| A. | k cal |
| B. | k cal/°K |
| C. | °K |
| D. | k cal. °K |
| Answer» D. k cal. °K | |
| 1087. |
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 Arrhenius 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. | |
| 1088. |
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 |
| A. | Use high pressure and eliminate inerts, when a > b |
| B. | Avoid recycle, when a > b |
| C. | Use batch reactor or plug flow reactor, when a > b |
| D. | Use CSTR with a high conversion, when a > b |
| Answer» C. Use batch reactor or plug flow reactor, when a > b | |
| 1089. |
A high space velocity means that a given |
| A. | Reaction can be accomplished with small reactor |
| B. | Conversion can be obtained with a high feed rate |
| C. | Both (A) and (B) |
| D. | None of these |
| Answer» D. None of these | |
| 1090. |
Design of heterogamous catalytic reactor involves consideration of __________ steps |
| A. | Only chemical |
| B. | Only physical |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 1091. |
Signal normally used to study non-ideal flow by stimulus response technique is __________ input. |
| A. | Pulse |
| B. | Step |
| C. | Both (A) & (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 1092. |
Holding time for flow reactors is __________ the space time, for constant fluid density |
| A. | Double |
| B. | Triple |
| C. | Equal to |
| D. | None of these |
| Answer» D. None of these | |
| 1093. |
The effect of increasing pressure on the gaseous equilibrium of the reaction www.objectivebooks.com 2X + 3Y ⇌ 3X + 2Y indicates that |
| A. | Pressure has no effect |
| B. | Backward reaction is favoured |
| C. | Forward reaction is favoured |
| D. | None of these |
| Answer» B. Backward reaction is favoured | |
| 1094. |
The reactions of high molecularity are rare, because |
| A. | Of very large activation energy of many bodies |
| B. | Of low probability of many body collisions |
| C. | Many body collisions are not favoured energetically |
| D. | Of requirement of very large concentration for such reactions |
| Answer» C. Many body collisions are not favoured energetically | |
| 1095. |
For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to 1/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times. |
| A. | 8 |
| B. | 16 |
| C. | 1/8 |
| D. | 1/16 |
| Answer» C. 1/8 | |
| 1096. |
The role of a catalyst in a chemical reaction is to change the |
| A. | Equilibrium constant |
| B. | Activation energy |
| C. | Final products |
| D. | Heat of reaction |
| Answer» C. Final products | |
| 1097. |
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 | |
| 1098. |
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 | |
| 1099. |
Slurry reactors are characterised by the |
| A. | Lack of intraparticle diffusion resistance |
| B. | Presence of two mobile phases |
| C. | Both (A) and (B) |
| D. | Neither (A) nor (B) |
| Answer» D. Neither (A) nor (B) | |
| 1100. |
In an ideal tubular-flow reactor |
| A. | There is no mixing in longitudinal direction |
| B. | Mixing takes place in radial direction |
| C. | There is a uniform velocity across the radius |
| D. | All (A), (B) and (C) |
| Answer» E. | |