Tiêu đề UNIT 3 CHEMICAL KINETICS-1.pdf ✅

Page| 2 a) First b) Second c) Zero d) Third 9. For an endothermic reaction where, ∆H represents the enthalpy of the reaction in kJ/mol, the minimum value for the energy of activation will be a) Less than ∆H b) Zero c) More than ∆H d) Equal to∆H 10. The unit of rate constant for a zero order reaction a) L s −1 b) L mol−1 s −1 c) mol L −1 s −1 d) mol s −1 11. What is the formula to find value of t1/2 for a zero order reaction? a) k [R]0 b) 2k [R]0 c) [R]0 2k d) 0.693 k 12. For the reaction, A + B ⟶ C + D. The variation of the concentration of the products is given by the curve: a) X b) Y c) Z d) W 13. Acid hydrolysis of sucrose is a a) Pseudo first order reaction b) Zero order reaction c) Second order reaction d) Unimolecular reaction 14. For a first order reaction the graph log log [A] vs t is given below x is equal to a) 0.693 k b) k 2.303 c) − k 2.303 d) log log [A]0 15. The rate constant of a first order reaction is 4 × 10−3 sec−1 . At a reactant concentration of 0.02 M, the rate of reaction would be: a) 8 × 10−5 M sec−1 b) 4 × 10−3 M sec−1 c) 2 × 10−1 M sec−1 d) 4 × 10−1 M sec−1 16. The rate constant for the reaction, 2N2O5 → 4NO2 + O2 is 3.0 × 10−5 s −1 . If the rate is 2.4 × 10−5molL −1 s −1 then the concentration of N2O5(inmolL −1 ) is a) 0.04 b) 0.8 c) 0.07 d) 1.4 17. Activation energy of a reaction is: a) The energy released during the reaction b) The energy evolved when activated complex is formed
Page| 3 c) Minimum amount of energy needed to overcome the potential barrier of reaction d) The energy needed to form one mole of the product 18. The activation energy for a reaction is 9.0 Kcal/mol. The increase in the rate constant when its temperature is increased from 298 K to 308 K is: a) 10% b) 100% c) 50% d) 63% 19. The rate of first order reaction, A ⟶ Products, is 7.5 × 10−4mol litre−1 sec−1 . If the concentration of A is 0.5 mol litre−1 the rate constant is: a) 3.75 × 10−4 sec−1 b) 2.5 × 10−5 sec−1 c) 1.5 × 10−3 sec−1 d) 8.0 × 10−4 sec−1 20. 2N2O5 ⇌ 4NO2 + O2 For the above reaction which of the following is not correct above rates of reaction? a) −d[N2O5] dt = 2 d[O2] dt b) −2d[N2O5] dt = d[NO2] dt c) d[NO5] dt = 4 d[O2] dt d) −2d[N2O5] dt = 4 d[NO2] dt = d[O2] dt 21. A substance undergoes first order decomposition. The decomposition follows to parallel first order reactions as: The percentage distribution of B and C are: a) 80% B and 20% C b) 76.83% B and 23.17% C c) 90% B and 10% C d) 60% B and 40% C 22. In Arrhenius plot intercept is equal to a) −Ea/R b) ln ln A c) ln ln k d) a 23. Half-life period of a first order reaction is 1386 seconds. The specific rate constant of the reaction is: a) 5.0 × 10−2 s −1 b) 5.0 × 10−3 s −1 c) 0.5 × 10−2 s −1 d) 0.5 × 10−3 s −1 24. On addition of AgNO3 to NaCl, white ppt. occurs: a) Instantaneously b) With a measurable speed c) Slowly d) None of these 25. Which is correct about zero order reaction?
Page| 4 a) Rate of reaction depends on decay constant. b) Rate of reaction is independent of concentration. c) Unit of rate constant is conc −1 d) Unit of rate constant is conc −1 time −1 26. The half-life period of a first order reaction is 1 min 40 s. Calculate its rate constant. a) 6.93 × 10−3min −1 b) 6.93 × 10−3 s −1 c) 6.93 × 10−3 s d) 6.93 × 103 s 27. The reaction 2A + B + C → D + Eis found to be first order in A, second in B and zero order in C. What is the effect on the rate of increasing concentration of A, B and C two times? a) 72 times b) 8 times c) 24 times d) 36 times 28. In a reaction, the threshold energy is equal to: a) Activation energy + normal energy of reactants b) Activation energy – normal energy of reactants c) Activation energy d) Normal energy of reactants 29. Which one is not correct? a) Rate of zero order reaction depends upon initial concentration of reactant b) Rate of zero order reaction does not depend upon initial concentration of reactant c) t1/2 of first order reaction is independent of initial concentration of reaction d) t1/2 of zero order reaction is dependent of initial concentration of reaction 30. A reaction proceeds by first order, 75% of this reaction was completed in 32 min. the time required for 50% completion is a) 8 min b) 16 min c) 20 min d) 24 min 31. The rate of the reaction CCl3CHO + NO → CHCl3 + NO + COis equal to rate k[CCl3CHO][NO]. If concentration is expressed in mol/L. The unit of k is a) L mol−1 s −1 b) mol L −1 s −1 c) L 2mol−2 s −1 d) s −1 32. Observe the following reaction, 2A + B → C The rate of formation of C is 2.2 × 10−3mol L −1 . What is the value of − d[A] dt (mol L −1 ) ? a) 2.2 × 10−3 b) 1.1 × 10−3 c) 4.4 × 10−3 d) 5.5 × 10−3 33. The unit of rate constant of a third order chemical reaction is a) mol−1 L s −1 b) mol−1 s −2 c) mol L d) s −1mol−2L 2