Chemical Kinetics, GOC, Chemical Bonding

1. The unit of the rate of reaction for a gaseous substance is: a) mol L⁻¹ time⁻¹ b) atm time⁻¹ c) mol L d) atm L⁻¹
2. The rate constant (k) of a reaction: a) Depends on the initial concentration of reactants b) Depends on the pressure of the reaction c) Increases with an increase in temperature d) Is independent of temperature
3. The half-life period (t_1/2) of a first-order reaction: a) Depends on the initial concentration b) Is independent of the initial concentration c) Is proportional to the initial concentration d) Is inversely proportional to the initial concentration
4. Which of the following is an example of a zero-order reaction? a) Hydrolysis of ester b) H₂ + Cl₂ (hv applied) →2HCl (over water surface) c) Radioactive disintegration d) 2NO+O₂→2NO₂
5. The unit of the rate constant (k) for a first-order reaction is: a) mol L⁻¹ time⁻¹ b) L mol⁻¹ time⁻¹ c) time⁻¹ d) L² mol⁻² time⁻¹
6. The temperature coefficient of a reaction is the ratio of the rate constants at two temperatures differing by: a) 5^∘C b) 10^∘C c) 25^∘C d) 50^∘C
7. According to the Arrhenius equation, the rate constant (k) is related to the activation energy (E_a) by the equation: a) k=A⋅e^Ea/RT   b) k=A⋅e^−Ea/RT  c) k=e^Ea/RTA  d) k=A⋅RT
8. On plotting log10k versus T1 for a reaction, the slope is found to be:

 a) E_a/2.303R b) − E_a/2.303R c) E_a/R d) −E_a/R

• In an exothermic reaction, the potential energy of the reactants is: a) Less than the potential energy of the products b) Equal to the potential energy of the products c) Greater than the potential energy of the products d) Always zero
• For a reaction to occur, the colliding molecules must have: a) Sufficient kinetic energy b) Proper orientation c) Both (a) and (b) d) Any amount of energy
• The minimum energy required to convert a reactant into a product is called: a) Kinetic energy b) Potential energy c) Threshold energy d) Activation energy
• Which of the following is an example of a pseudo first-order reaction? a) 2NO+O₂→2NO₂ b) Hydrolysis of ethyl acetate in the presence of an acid c) 2HI→H₂+I₂ d) 2N₂O₅→4NO₂+O₂

13. The Arrhenius factor (A) in the Arrhenius equation is also known as: a) Activation energy b) Collision frequency factor c) Boltzmann factor d) Rate constant
14. The effect of a catalyst on a reaction is to: a) Increase the activation energy b) Decrease the heat of reaction (ΔH) c) Increase the rate of reaction by providing an alternative path d) Change the equilibrium constant
15. The decomposition of H₂O₂ is a first-order reaction. Which of the following is correct? a) The half-life is dependent on the initial concentration. b) The rate constant unit is L mol−1 time−1. c) The plot of [H₂O₂] vs time is a straight line. d) The half-life is independent of the initial concentration.
16. The activation energy of a reaction is 90 kJ mol^-1. The rate constant at 298 K is k₁​. At what temperature will the rate constant be double of k₁​?        a) 301 K b) 304 K c) 306 K d) 310 K.
17. The rate constant for a reaction is k=4.0×10⁻² L mol⁻¹ s⁻¹. What is the order of the reaction? a) 0 b) 1 c) 2 d) 3
18. The half-life of a radioactive substance is 30 minutes. The time taken for 7/8th of the original sample to decay is: a) 90 min b) 60 min c) 30 min d) 15 min
19. For the reaction A+B→ products, the rate law is Rate =k[A]². If the concentration of A is doubled, the rate of the reaction will: a) double b) become four times c) remain the same d) become half
20. For a reaction, the rate constant is k. If the temperature is increased from 298 K to 308 K, and the temperature coefficient is 2, the new rate constant will be: a) 2k b) 4k c) k d) k/2.
21. The VSEPR theory is used to predict the: A) Bond length B) Bond enthalpy C) Molecular geometry D) Bond order
22. According to VSEPR theory, the repulsion between lone pair-lone pair (lp-lp) is: A) Greater than lp-bp repulsion B) Less than lp-bp repulsion C) Equal to lp-bp repulsion D) Always zero
23. The shape of BF3​ molecule is: A) Linear B) Trigonal planar C) Tetrahedral D) Pyramidal
24. The shape of NH3​ molecule is: A) Linear B) Trigonal planar C) Tetrahedral D) Pyramidal
25. The hybridization of carbon in C₂​H₂​ (ethyne) is: A) sp B) sp2 C) sp3 D) dsp2
26. A double bond consists of: A) One σ bond and one π bond B) Two σ bonds C) Two π bonds D) One σ bond and two π bonds
27. Molecular Orbital Theory (MOT) explains: A) The shape of molecules B) The magnetic properties of molecules C) The formation of ionic bonds D) The hybridization of atoms
28. According to MOT, the total number of molecular orbitals formed is equal to: A) The number of bonding molecular orbitals B) The number of anti-bonding molecular orbitals C) The number of atomic orbitals combining D) The number of electrons in the molecule
29. Which of the following is a bonding molecular orbital? A) σ^∗ B) π^∗ C) σ D) All of the above
30. Which of the following is an anti-bonding molecular orbital? A) σ B) π C) σ^∗ D) All of the above
31. The bond order of He2​ molecule is: A) 0 B) 0.5 C) 1 D) 2
32. Which of the following molecules is paramagnetic? A) N₂​ B) O₂​ C) F₂​ D) C_2​
33. Which of the following molecules has a zero dipole moment? A) H₂​O B) NH₃​ C) CO₂​ D) HCl
34. The geometry of PCl5​ molecule is: A) Tetrahedral B) Trigonal bipyramidal C) Octahedral D) Square planar
35. The hybridization of P in PCl5​ is: A) sp3 B) sp3d C) sp³d² D) dsp²
36. 10. Markovnikov’s rule is primarily applicable to: (a) Nucleophilic substitution reactions (b) Elimination reactions (c) Electrophilic addition reactions (d) Free radical substitution reactions

37. An electrophile is a species that is: (a) Electron-rich (b) Electron-deficient (c) Negatively charged (d) A proton donor
38. Which of the following effects involves the delocalization of σ-electrons? (a) Inductive effect (b) Resonance effect (c) Hyperconjugation (d) Mesomeric effect
39. Which of the following bond fissions results in the formation of ions? (a) Homolytic fission (b) Heterolytic fission (c) Both homolytic and heterolytic fission (d) Neither homolytic nor heterolytic fission
40. The stability order of carbocations is: (a) 1^∘>2^∘>3^∘ (b) 3^∘>2^∘>1^∘ (c) CH₃⁺​>1^∘>2^∘ (d) All are equally stable
41. A molecule with an incomplete octet on a carbon atom and a positive charge is a: (a) Carbanion (b) Free radical (c) Carbocation (d) Electrophile (but specifically an ion)
42. Which of the following is an electron-withdrawing group by inductive effect (-I effect)? (a) −CH₃​ (b) −OH (c) −NH₂​ (d) −OCH₃​
43. Nucleophilic addition reactions are characteristic of: (a) Alkanes (b) Alkenes (c) Aldehydes and ketones (d) Aromatic compounds
44. The general formula for alkenes is: (a) C_n​H_2n+2​ (b) C_n​H_2n​ (c) C_n​H_2n−2​ (d) C_n​H_2n−6​
45. A homologous series is characterized by: (a) Same molecular formula (b) Different chemical properties (c) Successive members differing by a −CH₂​− unit (d) All members being gases at room temperature

Answer Key

1. b) atm time⁻¹
2. c) Increases with an increase in temperature
3. b) Is independent of the initial concentration
4. b) H₂​+Cl_2​ (hv applied) →2HCl (over water surface)
5. c) time⁻¹
6. b) 10∘C
7. b) k=A⋅e^−Ea/RT
8. b) −Ea​/2.303R
9. c) Greater than the potential energy of the products
10. c) Both (a) and (b)
11. d) Activation energy
12. b) Hydrolysis of ethyl acetate in the presence of an acid
13. b) Collision frequency factor
14. c) Increase the rate of reaction by providing an alternative path
15. d) The half-life is independent of the initial concentration.
16. c) 306 K
17. c) 2
18. a) 90 min
19. b) become four times
20. a) 2k
21. C) Molecular geometry
22. A) Greater than lp-bp repulsion
23. B) Trigonal planar
24. D) Pyramidal
25. A) sp
26. A) One σ bond and one π bond
27. B) The magnetic properties of molecules
28. C) The number of atomic orbitals combining
29. C) σ
30. C) σ∗
31. A) 0
32. B) O₂​
33. C) CO_2​
34. B) Trigonal bipyramidal
35. B) sp³d
36. (c) Electrophilic addition reactions
37. (b) Electron-deficient
38. (d) Mesomeric effect
39. (b) Heterolytic fission
40. (b) 3∘>2∘>1∘
41. (c) Carbocation
42. (b) -OH
43. (c) Aldehydes and ketones
44. (b) Cn​H2n​
45. (c) Successive members differing by a −CH₂​− unit