Catalysis multiple choice questions -B.Sc. First year (UG degree course) Semester second, Physical chemistry paper IV

B.Sc. First year Undergraduate degree course Semester second Physical chemistry paper IV

Chapter - Chemical kinetics and catalysis (catalysis MCQ)

1. A catalyst can be described as a substance that:

(a)    undergoes change to accelerate the rate of the reaction
(b)   increases the kinetic energy of the reactants
(c)    provides a path of lower activation energy for the reaction
(d)   lowers the potential energy of the products with respect to the energy of the reactants
2. A catalyst will affect the rate of the forward reaction by changing the
(a)   activation energy
(b)   heat of reaction
(c)    heat of formation
(d)   potential energy of the products
3. Which of the following is most likely to increase the rate of a reaction?
(a)    decreasing the temperature
(b)   increasing the volume of the reaction vessel
(c)    reducing the activation energy
(d)   decreasing the concentration of the reactant in the reaction vessel
4. All of the following are true statements concerning catalysts except
(a)    a catalyst will speed the rate-determining step
(b)   a catalyst will be used up in a reaction
(c)    a catalyst may induce steric strain in a molecule to make it react more readily
(d)   a catalyst will lower the activation energy of a reaction
5. At equilibrium
(a)    the forward reaction will continue
(b)   a change in reaction conditions may shift the equilibrium
(c)    the reverse reaction will not continue
(d)   both (a) and (b)
6. Which statement is not correct regarding the function of a catalyst?
(a)    it affects the rate of a chemical reaction
(b)   it lowers the energy of the product, causing the reaction to be more exothermic
(c)    it changes the mechanism of a reaction
(d)   it lowers the activation energy
7. Which of the following will lower the activation energy for a reaction?
(a)    increasing the concentrations of reactants
(b)   raising the temperature of the reaction
(c)    adding a suitable catalyst
(d)   there is no way to lower the activation energy of a reaction
8.The process in which reactants or products itself act as catalyst is called ------------
(a)    catalysis
(b)   positive catalysis
(c)    negative catalysis
(d)   auto-catalysis
9.The term "catalyst” was coined by -----------
(a)    Arrhenius
(b)   Ostwald
(c)    Berzelius
(d)   Michelson

10.Catalysts are -------
(a)   specific
(b)   non-specific
(c)    always solids
(d)   always liquid.
11.Activated complex is -------------.
(a)    stable intermediate
(b)   unstable intermediate
(c)    stable reactant
(d)   unstable product
12.Smaller the activation energy ------------- the rate of reaction.
(a)    lesser
(b)   greater
(c)    no change
(d)   constant
13.Enzyme catalyzed reactions are -----------than metal catalyzed reactions.
(a)    slower
(b)   equal
(c)    no change
(d)   faster
14.Enzyme catalysts are ------------,
(a)    complex sulphur compounds
(b)   complex nitrogenous compounds
(c)    complex phosphorous compounds
(d)   all of the above
15.which all reactants are present in a single phase is called
(a)    heterogeneous catalysis
(b)   homogeneous catalysis
(c)    elementary reaction
(d)   multicomponent reaction
16.A reaction in which all reactants are in the same phase is called
(a)    elementary
(b)   bimolecular
(c)    homogeneous
(d)   heterogeneous
17. Species that are formed in one step of reaction mechanism and used up in another step are called
(a)    catalysts
(b)   intermediates
(c)    inhibitors
(d)   activated complexes
18. A catalyst
(a)    does not react
(b)   reacts and is produced in one of the later steps of a reaction
(c)    reacts in an early step and is produced in a later step
(d)   reacts but is not produced

19. A catalyst
(a)    changes the free energy change of a reaction
(b)   is included in the balanced chemical equation for a reaction
(c)    changes the mechanisms for a reaction
(d)   slows down the rate of a reaction
20. Which one of the following statements is incorrect?
(a)    catalysts speed up a reaction by lowering the activation energy
(b)   heterogeneous catalysts are often found on a solid in contact with gaseous reactants
(c)    an automotive catalytic converter uses a catalyst to burn gasoline better for higher gas mileage
(d)   enzymes are biological catalysts
21. The energy needed to overcome for a reaction to occur is called:
(a)   activation energy
(b)   energy of vaporization
(c)    specific heat
(d)   potential energy
22. When a catalyst is added to a reaction system,
(a)   the reaction rate is changed
(b)   the equilibrium position of the reaction is shifted
(c)    the ΔH of the reaction is changed
(d)   all of these
23. A catalyst
(a)    may be in same phase with the reactants or in a different phase
(b)   may accelerate a reaction
(c)    affects a reaction without being consumed in the process
(d)   all of the above