This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Chemistry Part I > Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics – Quiz 6 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 6 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the significance of a catalyst in enhancing reaction rates? A) A catalyst is a substance that increases the energy required for a reaction to occur. B) A catalyst is a substance that remains unchanged after the reaction and speeds it up. C) A catalyst is a reactant that is fully consumed during the reaction. D) A catalyst is a product that forms as a result of the reaction. Show Answer Correct Answer: B) A catalyst is a substance that remains unchanged after the reaction and speeds it up. 2. For which order reaction units of rate constant and rate of reaction are same A) First order. B) Zero order. C) Second order. D) None of the above. Show Answer Correct Answer: B) Zero order. 3. What does [ ] denote? A) Concentration, mass %. B) Concentration, m. C) Squared. D) Concentration, M. Show Answer Correct Answer: D) Concentration, M. 4. What does the term 'molecularity' refer to? A) The number of molecules involved in an elementary reaction. B) The concentration of reactants. C) The rate of a reaction. D) The number of steps in a reaction. Show Answer Correct Answer: A) The number of molecules involved in an elementary reaction. 5. What is the formula for change in enthalpy ( $\Delta$ A) PE of products + reactants. B) PE of Reactants + Products. C) PE of reactants-products. D) PE of products-reactants. Show Answer Correct Answer: D) PE of products-reactants. 6. Explain the concept of activation energy and its significance in chemical kinetics. A) Activation energy is only relevant in biological processes. B) Activation energy is constant for all reactions. C) Activation energy is crucial in determining the rate of chemical reactions by influencing the likelihood of successful collisions between reactant molecules. D) Activation energy has no impact on chemical reactions. Show Answer Correct Answer: C) Activation energy is crucial in determining the rate of chemical reactions by influencing the likelihood of successful collisions between reactant molecules. 7. Arrhenius equation is A) K = Ae$^{-RT/Ea}$. B) K = Ae$^{RT/Ea}$. C) K = Ae$^{-Ea/RT}$. D) K = Ae$^{Ea/RT}$. Show Answer Correct Answer: C) K = Ae$^{-Ea/RT}$. 8. Which one of the following is a second order, overall reaction A) K$_{1}$= 5403.2 M$^{1/2}$ s$^{1/2}$. B) K$_{1}$= 1.000 M s$^{-1}$. C) K$_{1}$= 10.7 s$^{-1}$. D) K$_{1}$= 1.23 x 10$^{-6}$ M$^{-1}$ s$^{-1}$. Show Answer Correct Answer: D) K$_{1}$= 1.23 x 10$^{-6}$ M$^{-1}$ s$^{-1}$. 9. The half life of the first order reaction having rate constant K = 1.7 x 10$^{-5}$s$^{-1}$ is A) 12.1 h. B) 1.8 h. C) 9.7 h. D) 11.3 h. Show Answer Correct Answer: D) 11.3 h. 10. Increasing the temperature increases the rate of a reaction by A) Lowering the frequency of effective collisions between reacting molecules. B) Increasing the frequency of effective collisions between reacting molecules. C) Increasing the activation energy. D) Lowering the activation energy. Show Answer Correct Answer: B) Increasing the frequency of effective collisions between reacting molecules. 11. A hypothetical reaction 2 p+q $\rightarrow$ s+r has rate constant as 2.0 x 10$^{-3}$ mol lit$^{-1}$ sec$^{-1}$, The order of the reaction is A) One. B) Zero. C) Two. D) Unpredictable. Show Answer Correct Answer: B) Zero. 12. A catalyst alters, which of the following in a chemical reaction? A) Enthalpy. B) Activation energy. C) Entropy. D) Internal energy. Show Answer Correct Answer: B) Activation energy. 13. For a second-order reaction, if the initial concentration is doubled, how does the half-life change? A) Remains constant. B) Halves. C) Doubles. D) Quadruples. Show Answer Correct Answer: C) Doubles. 14. If there is only single substance (atom, molecule, or ion) involved in the rate-determining step, that reaction is said to be A) Unimolecular. B) Trimolecular. C) Polimolecular. D) Bimolecular. Show Answer Correct Answer: A) Unimolecular. 15. Catalyst does not change the ..... A) Rate. B) Equilibrium constant. C) Equilibrium speed. D) Speed. Show Answer Correct Answer: B) Equilibrium constant. 16. Which of the following statements is true about a catalyst in a chemical reaction? A) It provides an alternative pathway with lower activation energy. B) It is consumed in the reaction. C) It changes the equilibrium position of the reaction. D) It increases the activation energy of the reaction. Show Answer Correct Answer: A) It provides an alternative pathway with lower activation energy. 17. If the temperature of a reaction is increased from 300K to 310K and the rate doubles, the activation energy of the reaction is approximately A) 65 kJ/mol. B) 62 kJ/mol. C) 100 kJ/mol. D) 52 kJ/mol. Show Answer Correct Answer: D) 52 kJ/mol. 18. Rate of reaction increase with increase in concntration A) NO. B) Yes. C) All the above. D) None of the above. Show Answer Correct Answer: B) Yes. 19. What is the term for the energy required to initiate a reaction? A) Activation energy. B) Thermodynamic energy. C) Kinetic energy. D) Potential energy. Show Answer Correct Answer: A) Activation energy. 20. What is a pseudo-rate law? A) A rate law that is incomplete, due to lacking orders. B) A rate law that represents the abstract concept of rate laws (Rate = k[A][B]), without specific reactants or orders. C) A rate law that is result of the simplification of a more complex rate law. D) A rate law that does not have any variables calculated. E) A rate law that is false. Show Answer Correct Answer: C) A rate law that is result of the simplification of a more complex rate law. 21. For an overall reaction order of 1, what will rate constant "k" have for its units? A) 1/M2 x s or M$^{-2}$ x s$^{-1}$. B) 1/Mxs or M$^{-1 }$x s$^{-1}$. C) M/s or M x s$^{-1}$. D) 1/s or s $^{-1}$. Show Answer Correct Answer: D) 1/s or s $^{-1}$. 22. Decreasing the concentration of a substance will usually ..... A) Slow down the reaction. B) Speed up the reaction. C) Have no affect on the reaction. D) None of the above. Show Answer Correct Answer: A) Slow down the reaction. 23. Write the rate law for the reaction aA $\rightarrow$ bB if the reaction is third order in A. [B] is not part of the rate law. A) Rate =k[A]$^{3}$. B) Rate =k[A]. C) Rate =3[A]. D) Rate =k[3A]. Show Answer Correct Answer: A) Rate =k[A]$^{3}$. 24. Name the compound, N$_{2}$O$_{5}$ A) Nitrogen Pentoxide. B) Dinitrogen (V) oxide. C) Dinitrogen Pentoxide. D) Dinitrogen Oxide. Show Answer Correct Answer: C) Dinitrogen Pentoxide. 25. Consider a reaction aG + bH $\rightarrow$ Products. Whenconcentration of both the reactants G and H is doubled, the rate increases by eight times. However, whenconcentration of G is doubled keeping the concentrationof H fixed, the rate is doubled. The overall order of thereaction is: A) 3. B) 0. C) 1. D) 2. Show Answer Correct Answer: A) 3. 26. Rate = k[A]The rate constant in the rate law above is 0.5 L/mols. If the initial concentration of A is 0.1 M, how long will it take for [A] to drop to 0.025 M? A) 0.7 s. B) 2.8 s. C) 1.4 s. D) There is not enough information given. Show Answer Correct Answer: B) 2.8 s. 27. How can the rate law of a chemical reaction be determined experimentally? A) By guessing based on intuition. B) By flipping a coin. C) By asking a magic eight ball. D) By conducting experiments with varying reactant concentrations and analyzing the data obtained. Show Answer Correct Answer: D) By conducting experiments with varying reactant concentrations and analyzing the data obtained. 28. For a first-order reaction with a rate constant k=0.693 min$^{-1}$, what is its half-life? A) 1min. B) 2min. C) 3min. D) 4min. Show Answer Correct Answer: A) 1min. 29. The half-life period of a first-order process A) Depends on reactant concentration raised to the first power. B) Is inversely proportional to square of reactant concentration. C) Is inversely proportional to reactant concentration. D) Is totally independent of reactant concentration. Show Answer Correct Answer: D) Is totally independent of reactant concentration. 30. The rate law for a reaction is rate = k [A][B]2 Which one of the following statements is false? A) If [B] is doubled, the reaction rate will increase by a factor of 4. B) The reaction is second order in B. C) The reaction is first order in A. D) The reaction is second order overall. Show Answer Correct Answer: D) The reaction is second order overall. 31. The collision frequency increases when: A) Temperature increases. B) Reactant concentration increases. C) Both (A) and (B). D) None. Show Answer Correct Answer: C) Both (A) and (B). 32. Pseudo zero order depends on: A) ONCE CONCENTRATION THAT IS VERY HIGH OR CONSTANT. B) RATE CONSTANT DOES NOT DEPEND ON CONCENTRATION. C) RATE DOES NOT CHANGE WITH CONCENTRATION. D) None of the above. Show Answer Correct Answer: A) ONCE CONCENTRATION THAT IS VERY HIGH OR CONSTANT. 33. What is the significance of the rate constant in a rate law? A) The rate constant indicates the speed of a reaction and its dependence on temperature and activation energy. B) The rate constant determines the final products of a reaction. C) The rate constant measures the concentration of reactants. D) The rate constant is only relevant at equilibrium. Show Answer Correct Answer: A) The rate constant indicates the speed of a reaction and its dependence on temperature and activation energy. 34. Which of the following is expressions represents correctly rate of following reaction?X + Y $\rightarrow$ Z + Q $\Delta$H = +22kj/mol A) Rate = +$\Delta$[Z] / $\Delta$t. B) Rate =-$\Delta$[Q] / $\Delta$t. C) Rate = +$\Delta$[Y] / $\Delta$t. D) Rate = +$\Delta$[X] / $\Delta$t. Show Answer Correct Answer: A) Rate = +$\Delta$[Z] / $\Delta$t. 35. A reaction is most likely to occur when the colliding particles have proper orientation and A) Energy. B) Volume. C) Half-life. D) Mass. Show Answer Correct Answer: A) Energy. 36. How much energy is released when two moles of methane (CH$_{4}$) reacts at 298 K and 101.3 kPa according to the following equation:CH$_{4}$(g) + 2O$_{2}$(g) $\rightarrow$ CO$_{2}$(g) + 2H$_{2}$O(l) A) 890.4 J. B) 890.4 kJ. C) 1780.4 kJ. D) 1780.4 J. Show Answer Correct Answer: C) 1780.4 kJ. 37. For a second-order reaction, what is the unit of the rate of the reaction? A) S$^{-1}$. B) Mol$^{-2}$ L$^{2}$ s$^{-1}$. C) Mol L$^{-1}$s$^{-1}$. D) Mol$^{-1}$ L s$^{-1}$. Show Answer Correct Answer: D) Mol$^{-1}$ L s$^{-1}$. 38. The half-life of a first-order reaction is independent of: A) Activation energy. B) Initial concentration. C) Reaction mechanism. D) Temperature. Show Answer Correct Answer: B) Initial concentration. 39. Given:A + 3B $\rightarrow$ 2C + DThis reaction is first order with respect to reactant A and second order with respect to reactant B. If the concentration of A is doubled and the concentration of B is halved, the rate of the reaction would ..... by a factor of ..... A) Decrease, 2. B) Not change. C) Increase, 4. D) Increase, 2. E) Decrease, 4. Show Answer Correct Answer: A) Decrease, 2. 40. Will an ENDOthermic reaction have a postive or negative change in enthalpy? A) $+\\Delta H$. B) $-\\Delta H$. C) All the above. D) None of the above. Show Answer Correct Answer: A) $+\\Delta H$. 41. Reaction rates generally decrease as temperature is increased. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 42. Which is NOT a factor that can be used to INCREASE the speed of a reaction? A) Higher temperature. B) Catalyst. C) Lower temperature. D) High Concentration of a solution. Show Answer Correct Answer: C) Lower temperature. 43. A rectilinear plot of concentration against time of a drug that is degrading by first order yields a declining straight line A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 44. Any substance that changes the rate of a reaction without being permanently changed or consumed A) Inhibitor. B) Enzyme. C) Catalyst. D) Activated complex. Show Answer Correct Answer: C) Catalyst. 45. Imagine a scenario where Abigail is conducting a chemistry experiment by mixing certain chemicals in a beaker, which reaches equilibrium. According to Le Chatelier's principle, if Abigail adds more of one reactant to the mixture, the system will: A) Increase the concentration of reactants. B) Shift in a direction that reduces the stress. C) Stop the reaction. D) Increase the temperature automatically. Show Answer Correct Answer: B) Shift in a direction that reduces the stress. 46. If activation energy is low, it is ..... for a reaction to start. A) Easy. B) Difficult. C) Neither. D) None of the above. Show Answer Correct Answer: A) Easy. 47. The slope of a semi-log plot of concentration (mcg/ml) against time (days) of a drug following apparent first order degradation is found to be-0.0032. Calculate the degradation rate constant. A) 7.37*10-3 day-1. B) 3.2*10-3 day-1. C) -3.2*10-3 day-1. D) -7.37*10-3 day-1. E) 1.39*10-3 day-1. Show Answer Correct Answer: A) 7.37*10-3 day-1. 48. The process of molecules of one substance collecting on the surface of another A) Adhesion. B) Cohesion. C) Adsorption. D) Absorption. Show Answer Correct Answer: C) Adsorption. 49. Not all collisions between reactant particles result in the formation of products. This could be due toi. the molecules not colliding with sufficient energyii. the concentration of reactants being lowiii. the reaction reaching equilibriumiv. the reactants not colliding in the correct orientation A) All of the above. B) I only. C) Iii only. D) I and iv. Show Answer Correct Answer: D) I and iv. 50. Define activation energy. A) The energy needed to maintain a reaction at equilibrium. B) The minimum energy required for a chemical reaction to occur. C) The energy released during a chemical reaction. D) The energy required to break chemical bonds. Show Answer Correct Answer: B) The minimum energy required for a chemical reaction to occur. 51. The rate constant of the reaction increases by ..... a) a. Increasing the temperatureb) b. Increasing the concentration of reactantsc) c. Carrying out the reaction for longer period d) d. Adding catalyst A) A. B) C. C) D. D) B. Show Answer Correct Answer: A) A. 52. Adding a catalyst to a chemical reaction results in A) A decrease in activation energy and a decrease in the reaction rate. B) A decrease in activation energy and an increase in the reaction rate. C) An increase in activation energy and a decrease in the reaction rate. D) An increase in activation energy and an increase in the reaction rate. Show Answer Correct Answer: B) A decrease in activation energy and an increase in the reaction rate. 53. Higher order(>3) reactions are rare due to A) Low probability of simultaneous collisions of all the reacting species. B) Increase in entropy and activation energy as more molecules are involved. C) Shifting of equilibrium towards reactants due to elastic collisions. D) Loss of active species on collision. Show Answer Correct Answer: A) Low probability of simultaneous collisions of all the reacting species. 54. Solid materials that are capable of adsorbing molecules of gases or liquids onto their surfaces are called ..... catalysts. A) Elementary. B) Organic. C) Heterogeneous. D) Complex. Show Answer Correct Answer: C) Heterogeneous. 55. How does one determine the order of reactants? For example, the orders of A and B in Rate = k[A][B]. A) Experimentally. B) The coefficients in the balanced equation. C) They are given. D) Graphing. Show Answer Correct Answer: A) Experimentally. 56. What is the relationship between reaction rate and concentration for a second order reaction? A) The reaction rate is proportional to the concentration raised to the first power. B) The reaction rate is constant regardless of concentration. C) The reaction rate is inversely proportional to the concentration. D) The reaction rate is proportional to the square of the concentration. Show Answer Correct Answer: D) The reaction rate is proportional to the square of the concentration. 57. What letter represents the activation energy in a reaction? A) H. B) A. C) E. D) G. Show Answer Correct Answer: B) A. 58. Which of the following is an appropriate dimension for the first order rate? A) Hour-1. B) Mole.lit-1. C) Cal/mole. D) Mg/hr. Show Answer Correct Answer: A) Hour-1. 59. What role do catalysts play in chemical reactions? A) Catalysts speed up chemical reactions by lowering activation energy. B) Catalysts change the products of the reaction to create new substances. C) Catalysts slow down chemical reactions by increasing activation energy. D) Catalysts are consumed in the reaction and do not affect the outcome. Show Answer Correct Answer: A) Catalysts speed up chemical reactions by lowering activation energy. 60. The rate of a reaction increases as temperature ..... A) Decreases. B) Increases. C) Stays the Same. D) None of the above. Show Answer Correct Answer: B) Increases. ← PreviousNext →Related QuizzesScience QuizzesClass 12 QuizzesClass 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 1Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 2Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 3Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 4Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 5Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 7Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 8Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books