chemical engineering Mcqs
3201. 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?
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A. 2

B. 3

C. 0.5

D. 1

3202. The synthesis of proteins and metabolism in biological objects occur in the presence of biocatalyst called_________________?
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A. A ferment or an enzyme

B. Fungi

C. Haemoglobin

D. None of these

3203. Radioactive decay follows ______________ order kinetics?
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A. First

B. Second

C. Zero

D. Third

3204. Good quality kerosene should have__________________?
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A. High aromatics content

B. High smoke point

C. Low paraffins content

D. Low smoke point

3205. The catalyst in a second order reversible reaction increases the rate of the forward reaction___________________?
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A. Only

B. To a greater extent than that of the backward reaction

C. And decreases that of backward reaction

D. And backward reaction equally
3206. The reason why a catalyst increases the rate of reaction is that, it______________?
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A. Increases the activation energy

B. Decreases the molecular collision diameter

C. None of these

D. Decreases the energy barrier for reaction
3207. Gum formation in stored gasoline is mainly due to the ____________________?
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A. Oxidation & polymerisation of unsaturated

B. Presence of sulphur

C. Alkylation of unsaturated

D. Higher aromatic content

3208. Salt content (measured as sodium chloride) in electrically desalted crude oil comes down to a level of about __________________ ptb (pounds per thousand barrel) ?
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A. 70

B. 35

C. 0.03

D. 3
3209. A batch reactor is_______________?
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A. Suitable for gas-phase reactions on commercial scale

B. Least expensive to operate for a given rate

C. Suitable for liquid phase reactions involving small production rate

D. Most suitable for very large production rate

3210. The temperature dependence of reaction rate constant (K) by Arrhenius law is given by_______________?
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A. K ? ?T . e-E/RT

B. K ? eE/RT

C. K ? T . e-E/RT

D. K ? e-E/RT
3211. Which of the following is the most suitable for isothermal operation?
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A. Fixed bed reactor

B. Back-mix reactor

C. Batch reactor

D. Plug-flow reactor

3212. When the density of the reaction mixture is constant in a chemical reaction, the ratio of the mean residence time to space time is__________________?
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A. 1

B. > 1

C. < 1

D. 0

3213. A high space velocity means that a given__________________?
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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

3214. Straight run naphtha is converted into high octane number petrol (gasoline) by catalytic____________________?
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A. Reforming

B. Polymerisation

C. Isomerisation

D. Cracking

3215. 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 _____________________?
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A. Temperature is increased and pressure is reduced

B. Temperature is reduced and pressure is increased

C. Pressure is reduced

D. Temperature is increased

3216. With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction_________________?
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A. Increases

B. Remain unaffected

C. Increases linearly with temperature

D. Decreases
3217. Holding time for flow reactors is _______________ the space time, for constant fluid density ?
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A. None of these

B. Double

C. Equal to

D. Triple

3218. Naphthenic acid is a/an ______________ compound?
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A. Sulphur

B. Nitrogen

C. Oxygen

D. None of these

3219. The rate at which a chemical substance reacts is proportional to its _____________________?
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A. Atomic weight

B. Active mass

C. Molecular weight

D. Equivalent weight

3220. If CA is the quantity of reactants initially present, the quantity left after n half periods will be equal to__________________?
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A. (CA/2)n

B. ()n CA

C. (CA)1/2n

D. (CA/2)1/n

3221. Enzymes are destroyed, when the_______________?
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A. Temperature is very high

B. Reactants concentration is very high

C. Reaction rate is independent of the reactants concentration

D. Reactants concentration is very low

3222. 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___________________?
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A. k cal. K

B. k cal/K

C. k cal

D. K
3223. Which of the following has maximum hydrogen/carbon ratio (by weight) ?
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A. Fuel oil

B. Gasoline

C. Naphtha

D. Diesel

3224. Transition state theory relates the above quantities as___________________?
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A. k ? e-E/RT

B. k ? T.eE/RT

C. k ? ?T

D. k ? T1.5

3225. An endothermic second order reaction is carried out in an adiabatic plug flow reactor. The rate of heat generation is ___________________?
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A. Maximum at the exit of the reactor

B. Maximum at the centre of the reactor

C. Maximum at the inlet of the reactor

D. Constant throughout the reactor

3226. Which of the following reactions is undesirable in the production of catalytically reformed gasoline ?
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A. Isomerisation of paraffins

B. Dehydrogenation of lower paraffins

C. Dehydrogenation of Naphthene

D. Dehydrocyclization of higher paraffins

3227. Which of the following is an independent variable for a batch tank reactor with uniform concentration and temperature ?
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A. Diameter of the reactor

B. Time

C. Useful volume of the tank

D. None of these

3228. Specific rate constant for a second order reaction__________________?
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A. Is independent of temperature

B. Varies with temperature

C. Depends on the nature of the reactants

D. Both B. and C.
3229. A catalyst in a chemical reaction _______________ free energy change in the reaction?
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A. Increases

B. Decreases

C. Either A. or B.; depends on the type of catalyst

D. Neither A. nor B.

3230. For a first order chemical reaction, the rate constant_________________?
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A. Is not a function of the unit of time

B. Has unit of time-1

C. Changes on changing the concentration units

D. None of these

3231. At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constants at 500K and 400K 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? ?
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A. 1.6

B. 2.5

C. 2

D. 2.24

3232. Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature ?
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A. Chemical reaction

B. Pore diffusion

C. Ash layer diffusion

D. Film diffusion
3233. 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?
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A. Either A. or B., depends on the type of reaction

B. No change

C. Decrease

D. Increase

3234. In a semi-batch reactor __________________?
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A. Condition similar to plug flow reactor exists

B. Velocity of reaction can be controlled

C. Residence time is constant

D. Mixing takes place in axial direction only

3235. 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?
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A. 32

B. 3-Jan

C. 3

D. 1

3236. The effect of increasing pressure on the gaseous equilibrium of the reaction 2X + 3Y ? 3X + 2Y indicates that____________________?
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A. Pressure has no effect

B. Forward reaction is favoured

C. Backward reaction is favoured

D. None of these

3237. Catalyst carriers___________________?
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A. Provide large surface area with a small amount of active material

B. Inhibit catalyst poisoning

C. Increase the activity of a catalyst

D. Have very high selectivity

3238. The molecularity and the order of reaction respectively, for the hydrolysis of methyl acetate in presence of acids are_______________?
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A. 2 & 2

B. 11 & 2

C. 2 & 1

D. 1 & 1

3239. The equilibrium constant for the reversible reaction as shown in the bellow figure, is affected by the__________________?
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A. Kinetics of the reaction

B. Temperature of the system

C. Presence or absence of inerts

D. Pressure of the system
3240. Which of the following will favour the reverse reaction in a chemical equilibrium reaction ?
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A. Increasing the concentration of one or more of the products

B. None of these

C. Removal of at least one of the products at regular interval

D. Increasing the concentration of one of the reactants

3241. consecutive reaction, as shown in the bellow figure, is characterised by __________________?
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A. High exothermicity

B. Maxima in the concentration of B

C. Maxima in the concentration of A

D. Maxima in the concentration of C

3242. Which parameter is used for the grading of paraffin waxes ?
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A. Penetration number

B. Viscosity

C. Melting point

D. Specific gravity

3243. 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 ?
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A. ln CA0 Vs ln t1/2

B. CA0 Vs ln t1/2

C. ln CA0 Vs t1/2

D. CA0 Vs t1/2

3244. A typical yield of diesel in straight run distillation of crude oil may be about ________________ percent?
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A. 18

B. 8

C. 28

D. 35

3245. When the reaction occurs in the diffusion controlled region, the apparent activation energy as measured is only _______________ the true value?
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A. Twice

B. Half

C. None of these

D. Equal

3246. Which of the following is an autocatalytic reaction ?
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A. Microbial fermentation reaction

B. Ammonia synthesis reaction

C. Enzyme fermentation reaction

D. Photochemical reactions

3247. The unit of frequency factor in Arrhenius equation is_______________?
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A. None of these

B. Same as that of rate constant

C. Same as that of activation energy

D. Dimensionless

3248. 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 ?
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A. First increases and then decreases

B. Is at the highest allowable temperature throughout

C. Increases

D. Decreases

3249. Conversion increases with increase in temperature in case of a/an ______________ reaction?
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A. Reversible endothermic

B. Reversible exothermic

C. Autocatalytic

D. Irreversible

3250. The decomposition of A into B is represented by the exothermic reaction, A ? 2B. To achieve maximum decomposition, it is desirable to carry out the reaction ?
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A. At low P and low T

B. At high P and high T

C. At high P and low T

D. At low P and high T