Reaction Kinetics Flashcards
Rate of chemical reaction is independent of the concentration of reactants for
A. Zero order reaction
B. Third order reaction
C. Consecutive reaction
D. None of these
A. Zero order reaction
Which of the following is not a unit of reaction rate?
A. Moles formed/(surface of catalyst)(time)
B. Moles formed/(volume of reactor)(time)
C. Moles formed/(volume of catalyst)(time)
D. None of these
D. None of these
If “n” is the order of reaction then unit of rate constant is
A. 1/(time)(concentration)^(n-1)
B. (time)-¹(concentration)^(n-1)
C. (time)^(n-1) (concentration)
D. None of these
A. 1/(time)(concentration)^(n-1)
Which of the following is a controlling factor in very fast heterogeneous reaction?
A. Heat and mass transfer effects
B. Pressure
C. Temperature
D. Composition of reactant
A. Heat and mass transfer effects
Variables affecting the rate of homogeneous reactions are
A. Pressure and temperature only
B. Temperature and composition only
C. Pressure and composition only
D. Pressure, temperature, and composition
D. Pressure, temperature, and composition
Rate determining step in a reaction consisting of a number of steps in series is the
A. Fastest step
B. Slowed step
C. Intermediate step
D. Data insufficient; can’t predict
B. Slowed step
Chemical kinetics can predict the
A. Rate of reaction
B. Feasibility of reaction
C. Both a and b
D. None of these
A. Rate of reaction
Velocity of a chemical reaction
A. Decreases with increase in temperature
B. Increases with increase of pressure of reactant for all reactions
C. Decreases with increase of reactant concentration
D. None of these
D. None of these
Sum of the powers of the concentration terms in the rate equation is called the
A. Order of the reaction
B. Overall order of the reaction
C. Molecularity of the reaction
D. None of these
B. Overall order of the reaction
Molecularity of a reaction
A. Is always equal to the overall order of reaction
B. May not be equal to the order of reaction
C. Can’t have a fractional value
D. Both b and c
D. Both b and c
Inversion of cane sugar is an example of
A. Unimolecular reaction with first order
B. Bimolecular reaction with second order
C. Bimolecular reaction with first order
D. Unimolecular reaction with second order
C. Bimolecular reaction with first order
Concentration of the limiting reactant (with initial concentration of a moles/liter) after time t is (a-x). Then t for a first order reaction is given by
A. kt=ln(a/a-x)
B. kt=x/a(a-x)
C. kt=ln(a-x/a)
D. kt=a(a-x)/X
A. kt=ln(a/a-x)
Half-life period of a chemical reaction is
A. The time required to reduce the concentration of the reacting substance to half its initial value
B. Half of the space time of a reaction
C. Half of the residence time of a reaction
D. None of these
A. The time required to reduce the concentration of the reacting substance to half its initial value
Half-life period for a first order reaction is _________ the initial concentration of the reactant
A. Directly proportional to
B. Inversely proportional to
C. Independent of
D. None of these
C. Independent of
In a first order reaction the time required to reduce the concentration of reactant from 1 mole/liter to 0.5 mole/liter will be ______ that required to reduce it from 10 moles/liter to 5 moles/liter in the same volume
A. More than
B. Less than
C. Same as
D. Data insufficient; can’t be predicted
C. Same as
Specific rate constant for a second order reaction
A. Is independent of temperature
B. Varies with temperature
C. Depends on the nature of the reactants
D. Both b and c
D. Both b and c
The reaction in which rate equation corresponds to a stoichiometric equation is called
A. Elementary reaction
B. Non-elementary reaction
C. Parallel reaction
D. Autokinetic reaction
A. Elementary reaction
Equilibrium of a chemical reaction as viewed by kinetics is a
A. Dynamic steady state
B. Static steady state
C. Dynamic unsteady state
D. None of these
A. Dynamic steady state
For a zero order reaction, concentration of product increases with
A. Increase of reaction time
B. Increase in initial concentration
C. Total pressure
D. Decrease in total pressure
A. Increase of reaction time
Arrhenius equation shows the variation of ______ with temperature
A. Reaction rate
B. Rate constant
C. Activation energy
D. Frequency factor
B. Rate constant
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
B. Is the minimum energy which the molecules must have before the reaction can take place
Rate constant “k” and the absolute temperature T are related by collision theory (for bimolecular) as
A. k ∝ T^(1.5)
B. k ∝ e^(-E/RT)
C. k ∝ T
D. None of these
C. k ∝ T
Transition state theory relates rate constant k and the absolute temperature T as
A. k ∝ e^(-E/RT)
B. k ∝ Te^(-E/RT)
C. k ∝ T
D. k ∝ T^(1.5)
B. k ∝ Te^(-E/RT)
Reactions with high activation energy are
A. Very temperature sensitive
B. Temperature insensitive
C. Always irreversible
D. Always reversible
A. Very temperature sensitive
In autocatalytic reactions
A. One of the reactants acts as a catalyst
B. One of the products acts as a catalyst
C. Catalyst has very high selectivity
D. No catalyst is used
B. One of the products acts as a catalyst
With increase in temperature, the equilibrium conversion of a reversible exothermic reaction
A. Decreases
B. Increases
C. Remain unaffected
D. Decreases linearly with temperature
A. Decreases
With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction
A. Decreases
B. Increases
C. Remain unaffected
D. Decreases linearly with temperature
A. Decreases
The equilibrium constant of a chemical reaction
A. Increases in the presence of catalyst
B. Decreases in the presence of catalyst
C. Remains unaffected in the presence of catalyst
D. Can either increase or decrease; depends on the type of catalyst
C. Remains unaffected in the presence of catalyst
Conversion increases with increase in temperature of
A. Autocatalytic reaction
B. Irreversible reaction
C. Reversible endothermic reaction
D. Reversible exothermic reaction
C. Reversible endothermic reaction
The heat of reaction
A. Depends on the pressure only
B. Depends on the mechanism of reaction only
C. Depends on both pressure and mechanism of reaction
D. Is independent of the mechanism of reaction
D. Is independent of the mechanism of reaction
Integral method for analyzing the kinetic data is used
A. When the data are scattered
B. For testing specific mechanisms with simple rate expression
C. Both a and b
D. None of these
C. Both a and b
Differential method for analyzing the kinetic data is used
A. For testing complicated mechanisms
B. When the data are scattered
C. When rate expressions are very simple
D. None of these
A. For testing complicated mechanisms
Exposure of a photographic plate to produce a latent image is an example of
A. Very slow reaction
B. Very fast reaction
C. Photochemical reaction
D. Both b and c
D. Both b and c
A trickle bed reactor is one which
A. Has altogether three streams either entering or leaving
B. Processes three reactants at different flow rates
C. Processes three reactants with same flow rate
D. Employs all the three phases (i.e. solid, liquid, and gas)
D. Employs all the three phases (i.e. solid, liquid, and gas)
According to Arrhenius equation of temperature dependency of rate constant for an elementary reaction
A. k ∝ √T
B. k ∝ e^(-E/RT)
C. k ∝ Te^(-E/RT)
D. None of these
B. k ∝ e^(-E/RT)
With increase in temperature, the rate constant obeying Arrhenius equation
A. Increases
B. Decreases
C. Decreases exponentially with temperature
D. Can either increase or decrease; depends on the frequency factor
A. Increases
A batch reactor is characterized by
A. Constant residence time
B. The variation in extent of reaction and properties of the reaction mixture with time
C. Variation in reactor volume
D. Very low conversion
B. The variation in extent of reaction and properties of the reaction mixture with time
A plug-flow reactor is characterized by
A. High capacity
B. Presence of axial mixing
C. Presence of lateral mixing
D. Constant composition and temperature of reaction mixture
C. Presence of lateral mixing
In a semi-batch reactor
A. Velocity of reaction can be controlled
B. Maximum conversion can be controlled
C. Both the reactants flow counter-currently
D. Residence time is constant
A. Velocity of reaction can be controlled
A back mix reactor
A. Is same as plug-flow reactor
B. Is same as ideal stirred tank reactor
C. Employs mixing in axial direction only
D. Is most suitable for gas phase reaction
B. Is same as ideal stirred tank reactor