MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 82 Mcqs, each offering curated multiple-choice questions to sharpen your Chemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a reaction, A + B → Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be written as |
| A. | Rate = k[A][B]2 |
| B. | Rate = k[A]2[B]2 |
| C. | Rate = k[A] [B] |
| D. | Rate = k[A]2[B] |
| Answer» E. | |
| 2. |
In the hydrolysis of an organic chloride in presence of large excess of water, RCl + H2O → ROH + HCl |
| A. | Moecularity is 1 and order of reaction is also 1 |
| B. | Molecularity is 2 but order of reaction is 1 |
| C. | Molecularity is 1 but order of reaction is 2 |
| D. | Molecularity and order of reaction both are 2 |
| Answer» C. Molecularity is 1 but order of reaction is 2 | |
| 3. |
The rate of a chemical reaction doubles for every 10°C rise of temperature. If the temperature is raised by 50°C, the rate of the reaction increases by about |
| A. | 10 times |
| B. | 32 times |
| C. | 64 times |
| D. | 24 times |
| Answer» C. 64 times | |
| 4. |
In a zero-order reaction for every 10° rise of temperature, the rate is doubled. If the temperature is increased from 10°C to 100°C, the rate of the reaction will become |
| A. | 512 times |
| B. | 256 times |
| C. | 128 times |
| D. | 64 times |
| Answer» B. 256 times | |
| 5. |
The activation energy of a reaction at a given temperature is found to be 303 RT J mol– The ratio of rate constant to the Arrhenius factor is |
| A. | 0.01 |
| B. | 0.02 |
| C. | 0.1 |
| D. | 0.001 |
| Answer» D. 0.001 | |
| 6. |
The rate equation for a reaction: A → B is r = K [A]°. If the initial concentration of the reactant is a mol dm–3, the half life period of the reaction is |
| A. | a/2k |
| B. | k/a |
| C. | a/k |
| D. | 2a/k |
| Answer» B. k/a | |
| 7. |
The time required for 100% completion of a zero order reaction is |
| A. | ak |
| B. | a/k |
| C. | a/2k |
| D. | 2k/a |
| Answer» C. a/2k | |
| 8. |
Radioactivity of a sample (z = 22) decreases 90% after 10 years. What will be the half-life of the sample? |
| A. | 2 years |
| B. | 5 years |
| C. | 3 years |
| D. | 10 years |
| Answer» D. 10 years | |
| 9. |
In a chemical reaction, only those collisions of molecules are effective in which the colliding molecules possess a minimum amount Of energy called? |
| A. | Average internal energy |
| B. | Activation energy |
| C. | Threshold energy. |
| D. | None of these |
| Answer» C. Threshold energy. | |
| 10. |
When one of the products of reaction acts, as catalysts then 'such a process is called? |
| A. | Positive catalysts |
| B. | Bio-Catalysts |
| C. | None of these |
| D. | Auto catalysts |
| Answer» E. | |
| 11. |
Molecular reactions have usually? |
| A. | Fast Speed |
| B. | Moderate speed |
| C. | Slow speed |
| D. | None of these |
| Answer» C. Slow speed | |
| 12. |
When one of products is removed from the reaction, the direction of reverse reaction is |
| A. | Forward |
| B. | both (a) and (b) |
| C. | None |
| D. | Backward |
| Answer» B. both (a) and (b) | |
| 13. |
In the reaction: 2N0 + O2 → 2NO2 if the concentration of NO is halved, the rate will decrease by |
| A. | none of these |
| B. | 2 Times |
| C. | 3 Time |
| D. | 1/2 times |
| Answer» D. 1/2 times | |
| 14. |
Among the following reactions, the fastest one? |
| A. | Precipitation of AgCl by mixing AgNO3 and NaCI solutions |
| B. | Conversion of monoclinic sulphur to rhombic sulphur |
| C. | Rusting of iron |
| D. | Burning of coal |
| Answer» B. Conversion of monoclinic sulphur to rhombic sulphur | |
| 15. |
The chemical reactions in which reactants require high amount of activation energy Are generally? |
| A. | Fast |
| B. | Slow |
| C. | Spontaneous |
| D. | Instantaneous |
| Answer» E. | |
| 16. |
The rate of a reaction increases with the increase of concentration of reactants because? |
| A. | None of these |
| B. | Number of molecules per unit volume increases |
| C. | Number of collisions per unit time between the reacting molecules increase due to increase of No. of molecules of reactants |
| D. | The enthalpy change for the reaction decreases. |
| Answer» D. The enthalpy change for the reaction decreases. | |
| 17. |
In case of Slow reaction, if the temperature is increased by 10 K, then point out the false statement? |
| A. | Energy of activation decreases |
| B. | Average K.E decreases |
| C. | Threshold energy. increases |
| D. | Number of collisions ,get multiplied |
| Answer» C. Threshold energy. increases | |
| 18. |
Reaction between H2 and CL2 occurs in the presence of sunlight. Its rate is independent of concentration of H2 and Cl2 so it is order reaction, |
| A. | zero |
| B. | First |
| C. | Second |
| D. | Third |
| Answer» B. First | |
| 19. |
The activation energy (Ea), in kJ/mole, is: |
| A. | 8.314 |
| B. | 27 |
| C. | 183 |
| D. | 24 |
| Answer» D. 24 | |
| 20. |
The minimum additional energy, above the average internal energy, which the. reacting molecules must possess so that their collision result in a reaction is known as? |
| A. | Activation energy |
| B. | Average kinetic energy. |
| C. | Threshold energy . |
| D. | None of these |
| Answer» B. Average kinetic energy. | |
| 21. |
The slow rate of a particular chemical reaction might be attributed to which of the following? |
| A. | a low activation energy |
| B. | a high activation energy |
| C. | the presence of a catalyst |
| D. | the temperature is high |
| Answer» C. the presence of a catalyst | |
| 22. |
The catalyst in the above mechanism is: |
| A. | O3 |
| B. | O |
| C. | NO |
| D. | NO2 |
| Answer» D. NO2 | |
| 23. |
For a reaction: 2H2+2NO —–> 2H20 + N2 the rate law is R =K [H2][NO]2 The Order of the reaction is? |
| A. | None |
| B. | 1 |
| C. | 3 |
| D. | 2 |
| Answer» B. 1 | |
| 24. |
Determine the molar concentration of A after 140 seconds have elapsed. |
| A. | 0.5 |
| B. | 0.3 |
| C. | 0.36 |
| D. | 0.2 |
| Answer» D. 0.2 | |
| 25. |
If the catalyst in question 42 is added to the reactants, the value of the rate constant, k, would be: |
| A. | larger than that of the uncatalyzed reaction |
| B. | the same as that of the uncatalyzed reaction |
| C. | smaller than that of the uncatalyzed reaction |
| D. | impossible to determine |
| Answer» B. the same as that of the uncatalyzed reaction | |
| 26. |
The rate law (or rate equation) is: |
| A. | R = k[ClO2][OH-]2 |
| B. | R = k[ClO2]2[OH-]2 |
| C. | R = k[ClO2][OH-] |
| D. | R = k[ClO2]2[OH-] |
| Answer» E. | |
| 27. |
The specific rate constant, k, for radioactive beryllium–11 is 0.049 s– What mass of a 0.500 mg sample of beryllium-11 remains after 28 seconds? |
| A. | 0.125 mg |
| B. | 0.250 mg |
| C. | 0.0625 mg |
| D. | 0.375 mg |
| Answer» B. 0.250 mg | |
| 28. |
The intermediate in the above mechanism is: |
| A. | NO |
| B. | O3 |
| C. | NO2 |
| D. | O |
| Answer» D. O | |
| 29. |
A catalyst functions by: |
| A. | providing a reaction path with a lower activation energy |
| B. | lowering the energy of the reactants. |
| C. | lowering the energy of the products. |
| D. | increasing the equilibrium constant. |
| Answer» B. lowering the energy of the reactants. | |
| 30. |
Reaction rates increase with temperature because as the temperature increases: |
| A. | the activation energy increases |
| B. | the activation energy decreases. |
| C. | the equilibrium constant increases. |
| D. | the rate constant increases. |
| Answer» E. | |
| 31. |
A catalyst increases the rate of a reaction by: |
| A. | increasing the temperature. |
| B. | decreasing the activation energy. |
| C. | increasing the activation energy. |
| D. | decreasing the temperature. |
| Answer» C. increasing the activation energy. | |
| 32. |
The following reaction is found to be first order in H2 (g) and second order in NO (g). The rate law for this reaction is: 2NO (g) + 2H2-> N2 (g) + 2H2O (g) |
| A. | Rate = k[NO][H2]2 |
| B. | Rate = k[NO]2[H2]2/[N2][H2O]2 |
| C. | Rate = k[NO]2[H2]2 |
| D. | Rate = k[NO]2[H2] |
| Answer» E. | |
| 33. |
You would expect the half-life of phosphine at room temperature to be _____ than at 680° C. |
| A. | longer |
| B. | shorter |
| C. | Not enough information given. Must know DH to answer this. |
| D. | the same |
| Answer» B. shorter | |
| 34. |
Which of the following are catalysts: |
| A. | Br2 |
| B. | OBr2 |
| C. | H2O |
| D. | Both Br2 and OBr2 are catalysts. |
| Answer» B. OBr2 | |
| 35. |
For the following reaction DG° is 60 kJ/mole at 25° C. The equilibrium constant for this reaction at 25° C is: H2 (g) + I2 (g) « 2HI (g) |
| A. | 0.35 |
| B. | 86 |
| C. | 0.999 |
| D. | 05 x 10-3 |
| Answer» B. 86 | |
| 36. |
Which of the following are reaction intermediates: |
| A. | H2O |
| B. | Br- |
| C. | None are reaction intermediates |
| D. | OBr- |
| Answer» E. | |
| 37. |
The rate law for this reaction is: |
| A. | Rate = k[H2O2][OBr-] |
| B. | Rate = k[H2O2]2 [Br- ] |
| C. | Rate = k[H2O2]2 |
| D. | Rate = k[H2O2][Br-] |
| Answer» E. | |
| 38. |
What is the half-life of phosphine (problem 14) at 680° C? |
| A. | 35 s |
| B. | 0.029 s |
| C. | 0.014 s |
| D. | 55 s |
| Answer» B. 0.029 s | |
| 39. |
What is the order with respect to A? |
| A. | first |
| B. | second |
| C. | zero |
| D. | 1 |
| Answer» C. zero | |
| 40. |
Which of the following plots would be linear if the above data is plotted? |
| A. | ln[N2O5] V time (in sec.) |
| B. | ln[N2O5] V 1/T(K) |
| C. | 1/[N2O] V time (in sec.) |
| D. | [N2O5] V time (in sec.) |
| Answer» B. ln[N2O5] V 1/T(K) | |
| 41. |
The reaction intermediate is: |
| A. | there is none |
| B. | HOI |
| C. | I- |
| D. | OH- |
| Answer» C. I- | |
| 42. |
The age of the Shroud of Turin in determined by radiocarbon dating. A Geiger counter measures 12 counts per minute (c.p.m.) in a sample of the shroud compared to 15.4 c.p.m. from carbon-14 in a living organism. If the half life is 5760 years, what is the age of the shroud in years? The radioactive decay of carbon-14 follows first order kinetics. |
| A. | 5760 |
| B. | 674 |
| C. | 20 x 10-4 |
| D. | 330 |
| Answer» C. 20 x 10-4 | |
| 43. |
What is the numerical value of the rate constant, k? |
| A. | 20 |
| B. | 0.01 |
| C. | 100 |
| D. | 0.1 |
| Answer» C. 100 | |
| 44. |
What is the rate constant, k (include units)? |
| A. | 0.25 h-1 |
| B. | 0.50 h-1 |
| C. | 0.50 M-1h-1 |
| D. | 0.25 Mh-1 |
| Answer» D. 0.25 Mh-1 | |
| 45. |
The rate law consistent with the mechanism is: |
| A. | R = k[HOI][I-] |
| B. | R = k[H2O2][I-]2 |
| C. | R = k[I-]2 |
| D. | R = k[H2O2][I-] |
| Answer» E. | |
| 46. |
Determine the value of the rate constant, k (in sec-1). |
| A. | 200 |
| B. | 0.0707 |
| C. | 0.05 |
| D. | 6.93 x 10-3 |
| Answer» E. | |
| 47. |
The half life for the first order decomposition of nitromethane, CH3NO2, at 500K is 650 seconds. If the initial concentration of CH3NO2 is 0.500M, what will its concentration be (M) after 1300 seconds have elapsed? |
| A. | 0.14 |
| B. | 0.125 |
| C. | 0.25 |
| D. | 0.425 |
| Answer» C. 0.25 | |
| 48. |
In the reaction: 2B→ Product If the concentration of 'B' is doubled, the rate of reaction will increase by? |
| A. | Four times |
| B. | Three times |
| C. | None of these |
| D. | Two times |
| Answer» B. Three times | |
| 49. |
2N02 + 02 ——> P2 NO2 The above reaction is: |
| A. | Bimolecular |
| B. | Unimolecular |
| C. | Trimolecular |
| D. | None of these |
| Answer» D. None of these | |
| 50. |
What is the order of the reaction in HI? |
| A. | second |
| B. | one half |
| C. | minus one |
| D. | first |
| Answer» B. one half | |