Chemical Kinetics Mock Test – Class 12 Chemistry

1. In two initial-rate experiments, is unchanged. Increasing from to increases the rate from to . The order with respect to is closest to:

2. When first-order disappearance gives , the expression that produces a positive value of is:

3. The rate factors caused by doubling the concentration of a reactant are arranged for four partial orders. Which sequence is correct for orders , , , and , respectively?

4. For the constant-volume reaction , the tangent slope of the -versus- curve at a selected instant is . At the same instant, the tangent slope of the -versus- curve is:

5. Match each change in Column I with its effect in Column II.

6. The common-logarithm form of the Arrhenius equation is:

7. A gaseous decomposition follows

If the initial pressure of pure is and the total pressure at time is , the partial pressure of unreacted at time is:

8. Two reactions have equal rate constants at one temperature, but Reaction P has the larger activation energy. Which statement must be true at that temperature?

9. During an interval, a reactant concentration decreases from to . Its average rate of disappearance is:

10. A complete list of common factors that can influence reaction rate includes:

11. An energy profile has and . The reverse activation energy is:

12. A reaction obeys . Which unit belongs to ?

13. The approximate effect of a temperature rise is described by these statements.
Statement I: Many reactions become about two to three times faster over a limited temperature range.
Statement II: Every reaction rate must exactly double for each rise.
Statement III: The approximate factor can vary from one reaction to another.
The valid statements are:

14. Concentration data for a reaction are shown below.

Which conclusion is most consistent with the data?

15. A complex reaction differs from an elementary reaction because a complex reaction:

16. A proposed rate law is used to calculate from four independent initial-rate experiments. The values obtained are shown below.

All experiments were performed at the same temperature and catalyst condition. The most suitable conclusion is:

17. The common-logarithm form of the first-order rate equation is obtained using:

18. Absorbance, which is proportional to reactant concentration, is used to monitor a first-order reaction.

The predicted absorbance at is closest to:

19. Reactions P and Q have the same activation energy and are compared at the same temperature. If , then:

20. For a gaseous reaction obeying at fixed temperature, a graph of rate against should be:

21. Assertion: Raising the temperature can produce a large increase in reaction rate even when the average molecular energy increases only moderately.
Reason: The fraction of molecules lying beyond the activation-energy threshold can increase substantially.

22. Assertion: For the constant-volume reaction , the magnitude of the average rate of disappearance of equals the average rate of appearance of .
Reason: The stoichiometric coefficients of and are both unity.

23. The rate constant of a reaction doubles when the temperature rises from to . The activation energy is closest to:

24. Which set of observations most strongly supports first-order kinetics?

25. During two successive intervals, a reactant concentration falls from to in the first , and then from to in the next . The ratio of the first average disappearance rate to the second is:

26. A reaction has and . The enthalpy change for the forward reaction is:

27. Two experiments use identical initial concentrations and the same catalyst condition, but Experiment Q is performed at a higher temperature than Experiment P. If the reaction mechanism remains unchanged, the most likely result is:

28. During the constant-volume reaction , the concentration of decreases by in . If , the concentration of after the interval is:

29. At , a tangent drawn to a reactant concentration-time curve passes through the convenient points and . The instantaneous rate of disappearance of the reactant at is:

30. In the rate law , the rate constant is:

31. For a first-order reaction, the slope of a plot of against time is ______.

32. The rate constant of a reaction at an unknown temperature is ten times its value at . If , the unknown temperature is closest to:

33. A mechanism contains a fast step followed by the slow elementary step . Why is not usually accepted as the final overall rate law?

34. The units of rate constants are assessed through the statements below.
Statement I: The time dimension of is always reciprocal time for a rate law written in the usual concentration form.
Statement II: The concentration dimension of depends on the overall reaction order.
Statement III: The unit of reaction rate changes with reaction order.
The valid statements are:

35. The claim “doubling the concentration of any reactant always doubles the reaction rate” is unreliable because:

36. Under the rate law , which statement is correct?

37. The rate constant of a reaction has the same unit as the reaction rate. The overall order of the reaction is:

38. For an ideal zero-order reaction, the relationship between completion time and half-life is:

39. A -against- graph for zero-order disappearance begins at and crosses the time axis at . The half-life is:

40. Pressure-method statements for first-order kinetics are listed below.
Statement I: Temperature and volume should remain constant during the measurements.
Statement II: The measured total pressure can always be used directly as the remaining reactant pressure.
Statement III: The final pressure helps convert total-pressure data into the partial pressure of unreacted gas.
The valid statements are:

41. The Arrhenius equation is:

42. A mechanism is proposed as:


A claim states that the overall rate law must be simply because the net equation is . The claim is unreliable because:

43. The unit of a rate constant is . The reaction is:

44. Use the energy-profile description below. Path P and Path Q connect the same reactant-energy level to the same product-energy level. Path P has a much higher maximum than Path Q. If Path Q represents the catalysed route, the supported conclusion is:

45. For the true rate law

when is isolated by using it in large excess, the observed rate constant is:

46. Two straight lines are obtained on plots of against . Line P has slope , while Line Q has slope . Which conclusion is correct?

47. The following half-life data are obtained for one reaction.

The reaction order and rate constant are:

48. Assertion: Amounts may replace concentrations in a first-order integrated equation when the volume is constant.
Reason: The ratio of initial to remaining amount is then equal to the corresponding concentration ratio.

49. Reaction P has both a larger pre-exponential factor and a larger activation energy than Reaction Q. Their Arrhenius lines intersect at temperature . Which comparison is correct?

50. Complete the collision-theory relation.