General
✓✗Assertion: Order of a reaction can be fractional.
Reason: Molecularity of a reaction can be fractional.
Reason: Molecularity of a reaction can be fractional.
- Both Assertion and Reason are true and Reason is the correct explanation of Assertion
- Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- Assertion is true but Reason is false
- Both Assertion and Reason are false
General
✓✗A reaction has Ea = 75.2 kJ mol−1. By what factor does the rate increase when the temperature is raised from 27 °C to 37 °C? (R = 8.314 J K−1 mol−1)
- 2.0
- 1.1
- 5.3
- 2.6
General
✓✗A reaction has Ea = 2.303 × 8.314 × 300 J mol−1 ≈ 5.74 kJ mol−1. At 300 K, the ratio k/A is
- 10
- 0.1
- 0.01
- 1
General
✓✗The reaction 2NO + Br2 → 2NOBr follows the mechanism
NO + Br2 ⇌ NOBr2 (fast equilibrium)
NOBr2 + NO → 2NOBr (slow)
The overall order of the reaction is
NO + Br2 ⇌ NOBr2 (fast equilibrium)
NOBr2 + NO → 2NOBr (slow)
The overall order of the reaction is
- 4
- 2
- 1
- 3
General
✓✗Statement I: The rate of a reaction increases about two times for every 10 K rise in temperature because the collision frequency doubles.
Statement II: The fraction of molecules with energy equal to or greater than Ea nearly doubles for a 10 K rise.
Statement II: The fraction of molecules with energy equal to or greater than Ea nearly doubles for a 10 K rise.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
General
✓✗A first order reaction has a specific reaction rate of 10−2 s−1. How much time will it take for 20 g of the reactant to reduce to 5 g?
- 138.6 s
- 693.0 s
- 346.5 s
- 238.6 s
General
✓✗The number of collisions per second per unit volume of the reaction mixture is called the
- steric factor
- collision frequency
- activation energy
- frequency factor
General
✓✗A reaction 2A + B → C proceeds by the mechanism A + B → D (slow), D + A → C (fast). The rate law is
- rate = k[A][B]
- rate = k[A]2
- rate = k[A]2[B]
- rate = k[D][A]
General
✓✗The decomposition of NH4NO2 → N2 + 2H2O as an elementary step is
- bimolecular
- zero molecular
- termolecular
- unimolecular
General
✓✗The radioactive isotope with a half-life of 8 days decays by first order kinetics. The fraction remaining after 32 days is
- 0.2500
- 0.1250
- 0.0625
- 0.0312
General
✓✗For a zero order reaction, the time required to reduce the concentration from 1.0 M to 0.5 M is t1, and from 0.01 M to 0.005 M is t2. Then
- t2 = 100t1
- t1 = 10t2
- t1 = t2
- t1 = 100t2
General
✓✗Threshold energy is equal to
- activation energy − average energy of the reactants
- activation energy + average energy of the reactants
- enthalpy of reaction
- activation energy of the reverse reaction
General
✓✗The half-life of a first order reaction is
- 1/k[R]0
- [R]0/2k
- 0.693/k
- 2.303/k
General
✓✗A first order reaction is 25% complete in 30 min. The time needed for 75% completion is (log 4 = 0.602, log 3 = 0.477)
- 114 min
- 90 min
- 144 min
- 60 min
General
✓✗For the first order reaction A(g) → 2B(g) + C(g) at constant volume and temperature, starting with pure A at pressure p0, the total pressure becomes 2p0 after a time equal to
- one-third of a half-life
- one half-life
- two half-lives
- three half-lives