0% 0 Chemical Reaction Quiz 1 1 / 50 A catalyst is said to be a negative catalyst, if it _____? Reduces the value of equilibrium constant Retards the rate of reaction Does not initiate the reaction All A., B. and C. 2 / 50 A plug-flow reactor is characterized by _______? High capacity Presence of lateral mixing Constant composition and temperature of reaction mixture Presence of axial mixing 3 / 50 A photochemical reaction is ________? Accompanied with emission of light All A., B. & C. Catalysed by light Initiated by light 4 / 50 A batch reactor is________? Suitable for liquid phase reactions involving small production rate Most suitable for very large production rate Least expensive to operate for a given rate Suitable for gas-phase reactions on commercial scale 5 / 50 A reaction in which one of the products of reaction acts as a catalyst is called a/an _______ reaction? Catalytic Photochemical None of these Autocatalytic 6 / 50 A catalyst in a chemical reaction ________ free energy change in the reaction? Neither A. nor B. Increases Either A. or B.; depends on the type of catalyst Decreases 7 / 50 ?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_______? Temperature Neither A. nor B. Both A. & B. Pressure 8 / 50 A back mix reactor is_____? Same as ideal stirred tank reactor Ideal at very low conversion Suitable for gas phase reactions Same as plug flow reactor (PFR) 9 / 50 A batch reactor suffers from following disadvantage ? High labour and handling cost All A., B. and C. Poor product quality control High shutdown time requirement for emptying, cleaning and refilling 10 / 50 A catalyst loses its activity due to___________? Loss in surface area of the active component Covering of the catalytic active sites by a foreign substance Agglomeration of metal particles caused by thermal sintering of the solid surface All A., B. and C. 11 / 50 A balanced chemical reaction equation conforms to the law of_________? None of these Conservation of mass Gaseous volumes Avogadro?s hypothesis 12 / 50 A reaction which is catalysed by a base is catalysed by all substances which have a tendency to_________? Gain an electron None of these Lose a proton Gain a proton 13 / 50 A chemical reaction is of zero order, when the reaction rate is (where, CA = concentration of reactant) ? ? CA None of these Independent of temperature ? 1/CA 14 / 50 A reactor is generally termed as an autoclave, when it is a_______? Atmospheric pressure CSTR High pressure batch reactor High pressure tubular reactor Atmospheric pressure tank reactor 15 / 50 A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and kg respectively. The effective rate constant (keff) is given by_________? 1/keff = 1/k + 1/kg keff = (k+ kg)/2 keff = (kkg)1/2 keff = k + kg 16 / 50 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_______? Of different sizes Of such size that the ratio of their volumes is < 5 Equal in size None of these 17 / 50 A backmix reactor__________? Is most suitable for gas phase reaction Is same as ideal stirred tank reactor Employs mixing in axial direction only Is same as plug-flow reactor 18 / 50 _______ explains the mechanism of catalysis? Thermodynamics Collision theory None of these Activated complex theory 19 / 50 _______ catalytic reaction is involved in the thermal cracking of gas oil ? Heterogeneous Non-Heterogeneous Non-Homogeneous Homogeneous 20 / 50 A first order reaction requires two equal sized CSTR. The conversion is______? Less when they are connected in series More when they are connected in parallel Same whether they are connected in series or in parallel More when they are connected in series 21 / 50 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 _____? Data insufficient, can?t be predicted 0.33 0.5 1 22 / 50 A chemical reaction occurs, when the energy of the reacting molecules is _________ the activation energy of reaction? Less than More than Equal to or more than Equal to 23 / 50 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___________? None of the above External mass transfer Diffusion within the pellet Reaction 24 / 50 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 ? PFR followed by a CSTR PFR followed by a CSTR followed by a PFR CSTR followed by a PFR followed by a CSTR CSTR followed by a PFR 25 / 50 A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m3 and volumetric flow rate 1m3 /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m3. The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 k.mole/m3, the volume of the mixed flow reactor should be increased by a factor of________? 6 3 3-Jul 7 26 / 50 A first order reaction requires two unequal sized CSTR. Which of the following gives higher yield ? Either of the arrangement A. or B. will give the same yield Large reactor followed by smaller one Data insufficient, can?t be predicted Smaller reactor followed by larger one 27 / 50 _________ resistance is not involved in the combustion of a carbon particle? Ash Chemical reaction Gas film None of these 28 / 50 A liquid decomposes by irreversible first order kinetics and the half life period of this reaction is 8 minutes. The time required for 75% conversion of the liquid will be ______ minutes? 12 16 8 4 29 / 50 A photochemical reaction is ________ light? Initiated by Catalysed by Used to convert heat energy into Accompanied with emission of 30 / 50 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 ? III, II, I II, III, I I, II, III III, I, II 31 / 50 A multiple reaction may be classified as a _________ reaction? Consecutive or side Mixed All A., B. and C. Parallel or side 32 / 50 6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO2 and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant ? 75% 20% 95% 100% 33 / 50 A reaction which is catalysed by an acid is also catalysed by any substance, which has a tendency to __________? Lose an electron Gain a proton None of these Lose a proton 34 / 50 A catalyst promoter__________? Itself has very high activity Acts as a catalyst support All A., B. and C. Improves the activity of a catalyst 35 / 50 A catalyst inhibitor______? Lessens its selectivity May be useful for suppressing undesirable side reactions Is added in small quantity during the catalyst manufacture itself Bleaching of paper pulp is done with___________? All A., B. and C. 36 / 50 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? 3-Jan 3 1 32 37 / 50 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 ? First increases and then decreases Is at the highest allowable temperature throughout Decreases Increases 38 / 50 ?Unreacted core model? represents the reaction involving ________? Roasting of sulphide ores Manufacture of carbon disulphide from elements None of these Combustion of coal particles 39 / 50 A catalyst________? Cannot be recovered chemically unchanged at the end of a chemical reaction Is capable of reacting with any one of the reactants Lowers the activation energy of reacting molecules Initiates a reaction 40 / 50 A high space velocity means that a given___________? None of these Reaction can be accomplished with small reactor Conversion can be obtained with a high feed rate Both A. and B. 41 / 50 A non-catalytic chemical reaction of the type as shown in the bellow figure is called a ______ reaction? None of these Series Parallel Series-parallel 42 / 50 A batch reactor is characterised by ______? Very low conversion Constant residence time Variation in reactor volume Variation in extent of reaction and properties of the reaction mixture with time 43 / 50 A Catalyst ______? Changes the equilibrium constant of the reaction None of these Shortens the time to reach the equilibrium Increases the equilibrium concentration of the product 44 / 50 ?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_________? V V.n V/n 1/V 45 / 50 A batch reactor is suitable for___________? Obtaining uniform polymerisation products in highly exothermic reactions Large scale gaseous phase reactions Liquid phase reactions Achieving cent percent conversion of reactants into products 46 / 50 A catalyst in a chemical reaction______? Alters the reaction mechanism All A., B. and C. Decreases the activation energy Increases the frequency of collisions of reacting species 47 / 50 A pulse tracer is introduced in an ideal CSTR (with a mean residence time I) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be___________? 0.5? 0.693? 2? ?/0.693 48 / 50 _______ is the response curve for a step input signal from a reactor ? S-curve None of these C-curve I-curve 49 / 50 ?N? plug flow reactors in series with a total volume ?V? gives the same conversion as a single plug flow reactor of volume ?V? for ________ order reactions? Second Any First Third 50 / 50 A first order irreversible reaction, A ? 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? None of these Both the conversion as well as concentrations will be different Conversion in both will be the same but concentrations will be different Both conversion as well as concentration are same Provide Your Information Your score is The average score is 0% LinkedIn Facebook Twitter 0% Restart quiz Send feedback Share on facebook Facebook Share on twitter Twitter Share on whatsapp WhatsApp PrevChemical Process Quiz 12 Chemical Reaction Quiz 2Next
