Description : Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the (A) Activation energy (B) Equilibrium constant (C) Heat of reaction (D) None of these
Last Answer : (A) Activation energy
Description : The catalyst in a first order chemical reaction changes the (A) Equilibrium constant (B) Activation energy (C) Heat of formation of the product (D) Heat of reaction
Last Answer : (B) Activation energy
Description : What happens when a catalyst is added to a system at equilibrium? A The reaction follows an alternative pathway of lower activation energy. B The heat of reaction decreases. C The potential ... decreases. D The potential energy of the products decreases. E The rate of chemical reaction decreases.
Last Answer : A The reaction follows an alternative pathway of lower activation energy.
Description : Which one of the following statements regarding a catalyst is not correct? A An enzyme is a catalyst that only binds certain substrates. B An enzyme is a protein that is a highly ... increasing the activation energy. D Catalysts do not alter the equilibrium constant for a chemical reaction.
Last Answer : C Catalysts increase the rate of a reaction by altering the mechanism, thereby increasing the activation energy.
Description : Pick out the correct statement. (A) A catalyst does not change AH of the reaction (B) A catalyst changes the equilibrium point (C) Law of mass action was suggested by Le-Chatelier (D) The difference between the energy of reactants and that of the products is the activation energy
Last Answer : (A) A catalyst does not change AH of the reaction
Description : Pick out the wrong statement. (A) Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition (B) Alumina is added as a promoter to ... Arrhenius plot (D) Presence of inerts affects the equilibrium conversion of reactants in a chemical reaction
Last Answer : (C) Activation energy for a reaction is obtained from the intercept of the Arrhenius plot
Description : A catalyst is a substance which (a) Changes the equilibrium of a reaction so that the concentration of the product increases (b) Increases the rate of reaction and increases the equilibrium concentration of products (c) Hastens the attainment of equilibrium (d) Increases the activation energy
Last Answer : Ans:(c)
Description : Pick out the wrong statement. (A) A particular chemical reaction is more temperature sensitive at low temperatures (B) A very high value of equilibrium constant, K (K >> 1) indicates that the ... ) Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions
Last Answer : (C) The intercept of the Arrhenius plot is called the 'activation energy
Description : Pick out the wrong statement. (A) A catalyst does not alter the final position of equilibrium in a reversible reaction (B) A catalyst initiates a reaction (C) A catalyst is specific in reaction (D) A catalyst remains unchanged in chemical composition at the end the reaction
Last Answer : (B) A catalyst initiates a reaction
Description : For a heterogeneous catalytic reaction (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction (B) A relatively small amount of catalyst ... with the reactant (D) The surface of the catalyst does not play an important role during reaction
Last Answer : (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction
Description : Pick out the wrong statement. (A) Exit age description function (E) and internal age distribution function (I) are related as, E = -(dI/dθ) (B) Chemisorption studies are useful in the ... energy (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products
Last Answer : (D) A catalyst increases the potential energy barrier over which the reactants must pass to form products
Description : A catalyst (A) Initiates a reaction (B) Lowers the activation energy of reacting molecules (C) Is capable of reacting with any one of the reactants (D) Cannot be recovered chemically unchanged at the end of a chemical reaction
Last Answer : (C) Is capable of reacting with any one of the reactants
Description : Pick out the correct statement. (A) In catalytic reactions, the catalyst reacts with the reactants (B) A catalyst initiates a chemical reaction (C) A catalyst lowers the activation energy of ... molecules (D) A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction
Last Answer : (C) A catalyst lowers the activation energy of the reacting molecules
Description : A catalyst in a chemical reaction (A) Decreases the activation energy (B) Alters the reaction mechanism (C) Increases the frequency of collisions of reacting species (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Catalyst is a substance, which __________ chemical reaction. (A) Increases the speed of a (B) Decreases the speed of a (C) Can either increase or decrease the speed of a (D) Alters the value of equilibrium constant in a reversible
Last Answer : (C) Can either increase or decrease the speed of a
Description : The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst. (A) Increases (B) Decreases (C) Remain unaffected (D) Unpredictable from the data
Last Answer : (C) Remain unaffected
Description : The equilibrium constant of chemical reaction __________ in the presence of catalyst. (A) Increases (B) Decreases (C) Remain unaffected (D) Can either increase or decrease (depends on the type of catalyst)
Description : Enzymes increases the rate of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction
Last Answer : Answer : B
Description : Enzymes increase the rates of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction
Description : Enzymes accelerate the rate of reactions by (A) Increasing the equilibrium constant of reactions (B) Increasing the energy of activation (C) Decreasing the energy of activation (D) Decreasing the free energy change of the reaction
Last Answer : Answer : C
Description : 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)
Last Answer : (B) Is the minimum energy which the molecules must have before the reaction can take place
Description : The rate expression for a heterogeneous 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 ... R and A) (A) E (B) E + ΔHA (C) E + ΔHA - ΔHR ) (D) ΔHA + ΔHR
Last Answer : (C) E + ΔHA - ΔHR )
Description : Pick out the correct statement. (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state (C) A photochemical reaction is catalysed by ... occurs when the energy of the reacting molecule is less than the activation energy of the reaction
Last Answer : (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state
Description : Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C ... in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod
Last Answer : (C) Enzymes help in increasing the activation energy of the reaction
Description : Higher free energy of activation of a chemical reaction (at a given temperature) implies (A) Slower rate of reaction (B) Higher rate of reaction (C) Higher equilibrium conversion (D) Both (B) and (C)
Last Answer : (A) Slower rate of reaction
Description : Pick out the correct statement. (A) A catalyst speeds up the forward reaction but slows shown the reverse reaction (B) Addition of catalyst changes the equilibrium constant (C) Pressure changes do not change the equilibrium concentrations (D) The composition of equilibrium is changed by catalyst
Last Answer : (C) Pressure changes do not change the equilibrium concentrations
Description : Pick out the correct statement. (A) A chemical reaction accompanied by absorption of heat is called an exothermic reaction (B) A chemical reaction accompanied by evolution of heat is called an ... does not change on changing the concentration units (D) Chemical equilibrium state is dynamic in nature
Last Answer : (C) The rate constant for a first order reaction does not change on changing the concentration units
Description : Role of an enzyme in reactions is to/as (a) decrease activation energy (b) increase activation energy (c) inorganic catalyst (d) none of the above.
Last Answer : (a) decrease activation energy
Description : Pick out the correct statement. (A) A lower temperature favours the reaction of lower activation energy (B) The dispersion number for a reactor/vessel is uL/D (C) The rate controlling step in ... step (D) Pore volume and porosity of a catalyst is measured by BrunauerEmmett-Teller (BET) technique
Last Answer : (A) A lower temperature favours the reaction of lower activation energy
Description : The reason why a catalyst increases the rate of reaction is that, it (A) Decreases the energy barrier for reaction (B) Increases the activation energy (C) Decreases the molecular collision diameter (D) None of these
Last Answer : (A) Decreases the energy barrier for reaction
Description : A Catalyst (A) Increases the equilibrium concentration of the product (B) Changes the equilibrium constant of the reaction (C) Shortens the time to reach the equilibrium (D) None of these
Last Answer : (C) Shortens the time to reach the equilibrium
Description : A catalyst is said to be a negative catalyst, if it (A) Retards the rate of reaction (B) Reduces the value of equilibrium constant (C) Does not initiate the reaction (D) All (A), (B) and (C)
Last Answer : (A) Retards the rate of reaction
Description : The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the __________ energy. (A) Activation (B) Potential (C) Binding (D) Threshold
Last Answer : (A) Activation
Description : If the rate of a chemical reaction becomes slower at a given temperature, then the (A) Initial concentration of the reactants remains constant (B) Free energy of activation is lower (C) Entropy changes (D) Free energy of activation is higher
Last Answer : (D) Free energy of activation is higher
Description : Promoter (A) Initiates a chemical reaction and is a catalyst by itself (B) Alters 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)
Last Answer : (C) Increases the number of active centres by increasing the unevenness of catalyst surface and by creating discontinuities in the crystals
Description : In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants) (A) Addition of inert gas favours the forward reaction, when Δx is positive (B) Pressure has no effect on equilibrium, when Δn = ... any value of Δx (+ ve, - ve) or zero) (D) All 'a', 'b' & 'c'
Last Answer : D) All 'a', 'b' & 'c'
Description : The free energy change for a chemical reaction is given by (where, K = equilibrium constant) (A) RT ln K (B) -RT ln K (C) -R ln K (D) T ln K
Last Answer : (B) -RT ln K
Description : An enzyme promotes a chemical reaction by (A) Lowering the energy of activation (B) Causing the release of heat which acts as a primer (C) Increasing molecular motion (D) Changing the free energy difference between substrate and product
Last Answer : Answer : A
Description : The unit of equilibrium constant of a chemical reaction is the same as that of (A) Molar concentration (B) Temperature (C) Internal energy (D) None of these
Last Answer : (D) None of these
Description : When a catalyst increases the rate of chemical reaction, the rate constant (A) Decreases (B) Increases (C) Remain constant (D) Become infinite
Last Answer : (B) Increases
Description : 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)
Last Answer : (C) Either (A) or (B); depends on the type of catalyst
Description : Brunauer, 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 ... (except the first one) is involved in each of the evaporation process (D) None of these
Last Answer : (B) There is no dynamic equilibrium between successive layer
Description : Arrhenius equation represents graphically the variation between the __________ and temperature. (A) Rate of reaction (B) Frequency factor (C) Rate constant (D) Activation energy
Last Answer : (C) Rate constant
Description : Arrhenius equation shows the variation of __________ with temperature. (A) Reaction rate (B) Rate constant (C) Energy of activation (D) Frequency factor
Last Answer : (B) Rate constant
Description : Pick out the wrong statement. (A) Visible radiation provides the necessary activation energy in photochemical reactions (B) The order and molecularity of a complex reaction may not be the same (C) For ... rate constant (k) (D) Molecularity of the reaction is always a whole number greater than zero
Last Answer : (B) The order and molecularity of a complex reaction may not be the same
Description : In multistage equilibrium conversion of SO2 to SO3 (2SO2 + O2 ⇌ 2SO3 ), the reverse reaction becomes appreciable at a temperature of 550° C. The percentage equilibrium conversion of SO2 to ... some quantity of SO3 during intermediate stage (D) Maintaining low temperature & pressure in the converter
Last Answer : (C) Removing some quantity of SO3 during intermediate stage
Description : Pick out the wrong statement. (A) In a multistep reaction, the slowest step is the rate determining step (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature (C ... energy (D) Molecularity of a reaction cannot be zero but the order of a reaction can be zero
Last Answer : (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature
Description : Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one
Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same
Description : The minimum energy required to allow a chemical reaction to proceed is termed as the 'threshold energy '. Chemical reactions with low activation energy are: (A) Always irreversible (B) Insensitive to temperature changes (C) Mostly irreversible (D) Highly temperature sensitive
Last Answer : (B) Insensitive to temperature changes
Description : A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction. (A) Less than (B) Equal to (C) More than (D) Equal to or more than
Last Answer : (D) Equal to or more than