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 1 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Chemistry (Part I) Chapter 4 Chemical Kinetics Quiz 1 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the half-life of a zero order reaction? A) T1/2 = [A]0 / k. B) T1/2 = 1 / (k[A]0). C) T1/2 = k / [A]0. D) T1/2 = [A]0 / (2k). Show Answer Correct Answer: D) T1/2 = [A]0 / (2k). 2. Define the term 'reaction rate' in the context of chemical kinetics. A) The reaction rate is the temperature of a chemical reaction. B) The reaction rate is the amount of time it takes for a reaction to complete. C) The reaction rate is the total energy released during a reaction. D) The reaction rate is the speed of a chemical reaction, defined as the change in concentration of reactants or products over time. Show Answer Correct Answer: D) The reaction rate is the speed of a chemical reaction, defined as the change in concentration of reactants or products over time. 3. What happened to the rate of reaction, if concentration of reactant is 'zero order'. A) Rate of reaction will become double. B) Rate of reaction will become triple. C) Rate of reaction will become quadrapel. D) No affect to the rate of reaction. Show Answer Correct Answer: D) No affect to the rate of reaction. 4. Rate law for the reaction A+2B $\rightarrow$C is found to be Rate = K[A][B]Concentration of reactant 'B' is doubled keeping the concentration of 'A' constant, the value of rate constant will be ..... A) Doubled. B) Quadrupled. C) Halved. D) The same. Show Answer Correct Answer: D) The same. 5. Which equals the heat of reaction? A) Potential energy of the products plus potential energy of the reactants. B) Potential energy of the products minus potential energy of the reactants. C) Potential energy of the reactants plus potential energy of the products. D) Potential energy of the reactants plus potential energy of the products. Show Answer Correct Answer: B) Potential energy of the products minus potential energy of the reactants. 6. Which of the following changes that can be made to a chemical reaction will result in a greater proportion of successful collisions between reactant particles?I. addition of a catalystII. grinding reactant lumps into a powderIII. increasing the concentration of reactants A) I only. B) II and III only. C) I and II only. D) I, II and III. Show Answer Correct Answer: A) I only. 7. What is the effect of a catalyst on a chemical reaction? A) Increases activation energy. B) Decreases activation energy. C) Increases the temperature. D) Changes the equilibrium constant. Show Answer Correct Answer: B) Decreases activation energy. 8. According to the collision theory, for a reaction to occur: A) Reacting molecules must collide with sufficient energy and proper orientation. B) Reacting molecules must collide with low energy. C) The reaction must be exothermic. D) The reaction must be endothermic. Show Answer Correct Answer: A) Reacting molecules must collide with sufficient energy and proper orientation. 9. What is the effect of adding catalyst on the free energy change deltsG of a reaction A) Gibbs free energy increases. B) Gibbs free energy decreases. C) Gibbs free energy remains constant. D) None of these. Show Answer Correct Answer: C) Gibbs free energy remains constant. 10. How does pressure affect reaction rate? A) Decreased pressure increases reaction rate because particles collide more frequently. B) Increased pressure increases reaction rate because particles collide more frequently. C) Increased pressure increases reaction rate because particles collide less frequently. D) Decreased pressure increases reaction rate because particles collide less frequently. Show Answer Correct Answer: B) Increased pressure increases reaction rate because particles collide more frequently. 11. The rate constant of a reaction is 5.8 $\times$ A) 0$^{th}$ order. B) 3$^{rd}$ order. C) 1$^{st}$ order. D) 2$^{nd}$ order. Show Answer Correct Answer: D) 2$^{nd}$ order. 12. A reaction with a negative activation energy suggests: A) A complex mechanism. B) Spontaneous reaction. C) Endothermic reaction. D) Unusual behavior. Show Answer Correct Answer: D) Unusual behavior. 13. Which conditions will increase the rate of a chemical reaction? A) Decreased temperature and decreased concentration of reactants. B) Decreased temperature and increased concentration of reactants. C) Increased temperature and decreased concentration of reactants. D) Increased temperature and increased concentration of reactants. Show Answer Correct Answer: D) Increased temperature and increased concentration of reactants. 14. Consider the following mechanism. Step 1:O$_{3}$ $\rightarrow$ O$_{2}$ + O (fast)Step 2:O$_{3}$ + O $\rightarrow$ 2 O$_{2}$ (slow)What is the overall balanced equation? A) 3 O$_{3}$ $\rightarrow$ 2 O$_{2}$. B) O$_{3}$ $\rightarrow$ 3 O$_{2}$. C) 2 O$_{3}$ $\rightarrow$ 3 O$_{2}$. D) 4 O$_{3}$ $\rightarrow$ 3 O$_{2}$. Show Answer Correct Answer: C) 2 O$_{3}$ $\rightarrow$ 3 O$_{2}$. 15. What is dynamic equilibrium in the context of chemical kinetics? A) Dynamic equilibrium is the state where the rates of forward and reverse reactions are equal, leading to constant concentrations of reactants and products. B) Dynamic equilibrium occurs only at high temperatures. C) Dynamic equilibrium is when reactants are completely converted to products. D) Dynamic equilibrium is the point where no reactions occur. Show Answer Correct Answer: A) Dynamic equilibrium is the state where the rates of forward and reverse reactions are equal, leading to constant concentrations of reactants and products. 16. Which of the following factors does NOT affect the rate of a chemical reaction? A) Temperature. B) Color of reactants. C) Presence of a catalyst. D) Concentration of reactants. Show Answer Correct Answer: B) Color of reactants. 17. What would be my the overall order of this rate law? Rate=[A]$^{2}$[B]$^{1}$ A) 1st Order. B) 2nd Order. C) 0 Order. D) 3rd Order. Show Answer Correct Answer: D) 3rd Order. 18. Which of the options below does NOT affect the rate of a reaction? A) Time. B) Temperature. C) Catalyst. D) Concentration. Show Answer Correct Answer: A) Time. 19. Bimolecular means: A) 2 molecules react. B) 3 molecules react. C) 1 molecule reacts. D) None of the above. Show Answer Correct Answer: A) 2 molecules react. 20. The sun undergoes fusion reactions to produce light, this is an ..... A) Exothermic Reaction. B) Endothermic Reaction. C) All the above. D) None of the above. Show Answer Correct Answer: A) Exothermic Reaction. 21. Time required for 100% completion of a zero order reaction is if initial concentration is [R]$_{0}$ A) [R]$_{0/2K}$. B) [R]$_{0/K}$. C) [R]$_{0 K}$. D) 2K/[R]$_{0}$. Show Answer Correct Answer: B) [R]$_{0/K}$. 22. Explain the concept of rate-determining step in a chemical reaction. A) Rate-determining step in a chemical reaction is the slowest step that determines the overall rate of the reaction. B) Rate-determining step is the fastest step in a reaction. C) Rate-determining step occurs after the reaction is completed. D) Rate-determining step has no impact on the overall rate of the reaction. Show Answer Correct Answer: A) Rate-determining step in a chemical reaction is the slowest step that determines the overall rate of the reaction. 23. HI dissociates to form I$_{2}$ and H$_{2}$:2HI(g) $\rightarrow$ H$_{2}$(g) + I$_{2}$(g) If the concentration of HI changes at a rate of-0.50 M/s, what is the rate of appearance of H$_{2}$(g)? A) .25 M/s. B) .10 M/s. C) 1.0 M/s. D) The rate of appearance and disappearance are the same. Show Answer Correct Answer: A) .25 M/s. 24. Products will form faster if ..... A) Concentration of the reactants are increased. B) The particle size of the reactants are larger. C) The reaction is not stirred. D) Temperature is decreased. Show Answer Correct Answer: A) Concentration of the reactants are increased. 25. Zero order rate constant DOES NOT DEPEND ON CONCENTRATION A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 26. An ice cube melts into liquid water. This is an ..... A) Exothermic reaction. B) Endothermic reaction. C) All the above. D) None of the above. Show Answer Correct Answer: B) Endothermic reaction. 27. An ion-dipole force exists between an ion and a non-polar molecule. Cations are attracted to the negative end of a dipole, and anions are attracted to the positive end. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 28. The rate of a chemical reaction tells us about A) The reactants taking part in the reaction t. B) The products formed in the reaction. C) How slow or fast the reaction is taking place. D) None of the above. Show Answer Correct Answer: C) How slow or fast the reaction is taking place. 29. Which of the following affect the rate of the reaction as nature of the reactant A) Physical size of the reactant. B) Ionic or covalent substances. C) Both 1 and 2. D) None. Show Answer Correct Answer: C) Both 1 and 2. 30. What does the Arrhenius equation relate to? A) Concentration and time. B) Pressure and volume. C) Energy and mass. D) Rate of reaction and temperature. Show Answer Correct Answer: D) Rate of reaction and temperature. 31. True or False:David is conducting an experiment and writes the balanced chemical equation for his reaction. He wonders if he can determine the rate law directly from this equation. Is it true that rate laws are determined directly from the balanced chemical equation? A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 32. Activation energy is the ..... energy required to start a chemical rection A) Maxmimum. B) Minimum. C) All the above. D) None of the above. Show Answer Correct Answer: B) Minimum. 33. What does the rate of a reaction depend on? A) Only temperature. B) Only concentration. C) Only catalysts. D) Concentration, temperature, and catalysts. Show Answer Correct Answer: D) Concentration, temperature, and catalysts. 34. A chemical reaction occurs when reactant particles A) Are separated by great distances. B) Have no attractive forces between them. C) Collide with proper energy and proper orientation. D) Convert chemical energy into nuclear energy. Show Answer Correct Answer: C) Collide with proper energy and proper orientation. 35. What is the molecularity of a reaction? A) The rate of formation of products. B) The total concentration of reactants. C) The number of molecules involved in an elementary reaction. D) The number of steps in a reaction. Show Answer Correct Answer: C) The number of molecules involved in an elementary reaction. 36. How do you determine the order of a reaction experimentally? A) The order of a reaction is determined by the temperature alone. B) The order of a reaction is always equal to the stoichiometric coefficients of the reactants. C) The order of a reaction can be determined by analyzing the relationship between reactant concentrations and reaction rates. D) The order of a reaction can be found by measuring the volume of gas produced. Show Answer Correct Answer: C) The order of a reaction can be determined by analyzing the relationship between reactant concentrations and reaction rates. 37. How does surface area affect reaction rates? A) Increasing surface area allows more collisions between reactants, thus increasing the reaction rate. B) Decreasing surface area reduces the number of collisions, slowing down the reaction rate. C) Surface area has no effect on reaction rates; only temperature matters. D) Increasing surface area decreases the reaction rate by spreading reactants too thin. Show Answer Correct Answer: A) Increasing surface area allows more collisions between reactants, thus increasing the reaction rate. 38. Which of these will NOT speed up the rate of reaction between a strip of magnesium and hydrochloric acid? A) Increase the concentration of the hydrocholoric acid. B) Tightly coil up the strip of magnesium. C) Increase the temperature of the hydrocholoric acid. D) Cut up the strip of magnesium. Show Answer Correct Answer: B) Tightly coil up the strip of magnesium. 39. According to the results of Experiment 1, for any given catalyst, as the temperature was increased, the number of cycles needed to complete the reaction: A) Increased, then decreased. B) Decreased only. C) Decreased, then increased. D) Increased only. Show Answer Correct Answer: D) Increased only. 40. The pulverizing of a solid substances to increase reaction rate effective because pulverizing A) Increases the surface area. B) Reduces the bonding forces between molecules. C) Increases the temperature. D) Changes the chemical make-up of the reacting substances. Show Answer Correct Answer: A) Increases the surface area. 41. Step 1:O$_{3}$ $\rightarrow$ O$_{2}$ + Ostep 2:O$_{3}$ + O $\rightarrow$ 2 O$_{2}$The oxygen atom (O) is considered to be a(n) ..... $_{}$ A) Catalyst. B) Reactant. C) Activated complex. D) Reaction intermediate. Show Answer Correct Answer: D) Reaction intermediate. 42. Half-life of a pseudo zero-order reaction depends on the initial concentration of the reactant A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 43. Imagine Jackson is conducting a chemical experiment in his lab. He decides to increase the concentration of a reactant. What happens to the equilibrium position of the reaction? A) It shifts towards the products. B) It remains unchanged. C) It shifts towards the reactants. D) The reaction stops. Show Answer Correct Answer: A) It shifts towards the products. 44. Explain the difference between reaction rate and rate constant. A) Reaction rate is the same as the rate constant. B) The rate constant changes with temperature, while reaction rate does not. C) Reaction rate is a fixed value, whereas the rate constant varies with time. D) Reaction rate measures how fast a reaction occurs, while the rate constant is a specific value that relates the reaction rate to reactant concentrations. Show Answer Correct Answer: D) Reaction rate measures how fast a reaction occurs, while the rate constant is a specific value that relates the reaction rate to reactant concentrations. 45. An EXOthermic reaction will have a postive or negative $\Delta H$ A) $+\\Delta H$. B) $-\\Delta H$. C) All the above. D) None of the above. Show Answer Correct Answer: B) $-\\Delta H$. 46. What is the effect of concentration on the rate of a zero order reaction? A) The rate increases with higher concentration. B) The rate of a zero order reaction is unaffected by concentration. C) The rate is directly proportional to concentration. D) The rate decreases with higher concentration. Show Answer Correct Answer: B) The rate of a zero order reaction is unaffected by concentration. 47. For the reaction, NO$_{2}$ (g) + CO (g) $\rightarrow$ NO (g) +CO$_{2}$ (g), the correct expression for the rate of reaction is A) Rate =-d[NO$_{2}$]/dt. B) Rate = d[CO]/dt. C) Rate = \{d[NO$_{2}$]-d[CO]\}/dt. D) Rate =-d[CO$_{2}$]/dt. Show Answer Correct Answer: A) Rate =-d[NO$_{2}$]/dt. 48. Which of the following statements is correct? a The rate of a reaction decreases with passage of time as the concentration of reactants decreases.b The rate of a reaction is same at any time during the reaction. c The rate of a reaction is independent of temperature change. d The rate of a reaction decreases with increase in concentration of reactant(s). A) A. B) B. C) C. D) D. Show Answer Correct Answer: A) A. 49. A drug solution decomposes with a rate constant, k, of 0.0077 days-1. What is the half-life of the drug in solution? A) 90 hours. B) 5 hours. C) 90 days. D) 9 days. Show Answer Correct Answer: C) 90 days. 50. Rate law of a composite reaction is determined by a slowest step which is known as ..... A) Independent. B) Non determining step. C) Fastest step. D) Rate determining step. Show Answer Correct Answer: D) Rate determining step. 51. The rate law for the reaction 2NO$_{(g)}$ + O$_{2(g)}$ $\rightarrow$ 2NO$_{2(g)}$ is first order in O$_{2}$ and third order overall. What is the rate law for the reaction? A) Rate = k [2NO]$^{2}$[O$_{2}$]$^{1}$. B) Rate = k [NO]$^{2}$[O$_{2}$]$^{1}$. C) Rate = k [NO]$^{2}$[O$_{2}$]$^{2}$. D) Rate = k [NO]$^{1}$[O$_{2}$]$^{2}$. Show Answer Correct Answer: B) Rate = k [NO]$^{2}$[O$_{2}$]$^{1}$. 52. The reaction NO2 + CO $\rightarrow$ NO + CO2 takes place in two steps. 2NO2 $\rightarrow$ NO + NO3 (k1)-slow NO3 + CO $\rightarrow$ CO2 + NO2 (k2)-fast The rate law is A) R = k1 [NO2]3. B) R = k2 [NO3] [CO]. C) R = k1 [NO2]. D) R = k1 [NO2]2. Show Answer Correct Answer: D) R = k1 [NO2]2. 53. The overall rate of a reaction is governed by A) The rate of fastest intermediate step. B) The sum total of the rates of all intermediate steps. C) The average of the rates of all the intermediate steps. D) The rate of slowest intermediate step. Show Answer Correct Answer: D) The rate of slowest intermediate step. 54. When energy is absorbed, the reaction is described as ..... A) Zero order. B) First-order. C) Exothermic. D) Endothermic. Show Answer Correct Answer: D) Endothermic. 55. What is a second-order reaction? A) A reaction where the rate is independent of the concentration of reactants. B) A reaction with a rate proportional to the square of the concentration of one reactant or the product of the concentrations of two reactants. C) A reaction that occurs in a single step without intermediates. D) A reaction with a rate proportional to the concentration of one reactant. Show Answer Correct Answer: B) A reaction with a rate proportional to the square of the concentration of one reactant or the product of the concentrations of two reactants. 56. What does the rate constant (k) depend on? A) Only temperature. B) Only concentration. C) Pressure and volume. D) Temperature and concentration. Show Answer Correct Answer: D) Temperature and concentration. 57. 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) There is not enough information given. D) 1.4 s. Show Answer Correct Answer: B) 2.8 s. 58. Fora reaction, A+B $\rightarrow$ Product; the rate law is given by, r =k [ A]1/2 [B]2. What is the order of the reaction? A) 1. B) 1.5. C) 2.5. D) 2. Show Answer Correct Answer: C) 2.5. 59. For a reaction A$\rightarrow$B, r= A) -dA/dt. B) +dB/dt. C) -dB/dt. D) Both 1 and 2. Show Answer Correct Answer: D) Both 1 and 2. 60. If the concentration of a reactant is increased, the reaction rate will ..... A) Increase. B) Decrease. C) Stay the same. D) None of the above. Show Answer Correct Answer: A) Increase. 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