General
✓✗In general, the unit of the rate constant of an nth order reaction is
- (L mol−1)1−n s−1
- (mol L−1)n−1 s−1
- (mol L−1)n s−1
- (mol L−1)1−n s−1
General
✓✗A catalyst increases the rate of a reaction by
- increasing the enthalpy change
- providing an alternative path of lower activation energy
- increasing the activation energy
- increasing the temperature of the system
General
✓✗For a gaseous first order reaction A(g) → B(g) + C(g) at constant volume, the total pressure after a very long time is
- equal to the initial pressure
- half the initial pressure
- three times the initial pressure
- twice the initial pressure
General
✓✗For a zero order reaction, the plot of t1/2 against initial concentration [A]0 is
- a rectangular hyperbola
- a straight line through the origin
- a straight line parallel to the [A]0 axis
- an exponential decay curve
General
✓✗A zero order reaction has k = 0.0030 mol L−1 s−1. Starting with [A]0 = 0.30 mol L−1, the concentration of A after 40 s is
- 0.18 mol L−1
- 0.29 mol L−1
- 0.27 mol L−1
- 0.12 mol L−1
General
✓✗For a first order reaction, a plot of ln[R] against t gives a straight line with slope
- −k
- +k
- −k/2.303
- [R]0
General
✓✗For a first order reaction, the plot of t1/2 against initial concentration [A]0 is
- a straight line through the origin
- a straight line parallel to the [A]0 axis
- a rectangular hyperbola
- a straight line with negative slope
General
✓✗For a reaction, k = 1.0 × 10−2 s−1 at 400 K and k = 1.0 × 10−1 s−1 at 500 K. The activation energy is (R = 8.314 J K−1 mol−1)
- 1.9 kJ mol−1
- 19.1 kJ mol−1
- 16.6 kJ mol−1
- 38.3 kJ mol−1
General
✓✗A drawback of the simple collision theory is that it
- applies only to zero order reactions
- ignores collisions altogether
- considers atoms/molecules to be hard spheres and ignores their structural aspects
- cannot explain the effect of temperature
General
✓✗Given below are two statements: one is labelled as Assertion A and the other as Reason R.
Assertion A: All molecular collisions between reactant molecules lead to the formation of products.
Reason R: The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to the threshold value is called the activation energy.
In the light of the above statements, choose the correct answer from the options given below.
Assertion A: All molecular collisions between reactant molecules lead to the formation of products.
Reason R: The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to the threshold value is called the activation energy.
In the light of the above statements, choose the correct answer from the options given below.
- 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
- Assertion is false but Reason is true
General
✓✗For the gaseous reaction 2NO(g) + O2(g) → 2NO2(g) in a closed vessel, the total pressure
- first increases then decreases
- decreases as the reaction proceeds
- remains constant
- increases as the reaction proceeds
General
✓✗For the rate law rate = k[A]2[B], if the concentration of A is halved and B is doubled, the rate
- remains the same
- doubles
- becomes one-fourth
- becomes half
General
✓✗A reaction has Ea = 11.5 kJ mol−1. The fraction of molecules having energy equal to or greater than Ea at 300 K is about (R = 8.314 J K−1 mol−1)
- 0.010
- 0.001
- 0.500
- 0.100
General
✓✗The concentration of a product rises from 0.02 M to 0.05 M in 5 minutes. The average rate of formation of the product is
- 3 × 10−2 mol L−1 min−1
- 1.5 × 10−1 mol L−1 min−1
- 1 × 10−2 mol L−1 min−1
- 6 × 10−3 mol L−1 min−1
General
✓✗The overall reaction 2NO + O2 → 2NO2 follows rate = k[NO]2[O2]. If the first step NO + NO ⇌ N2O2 is a fast equilibrium, the slow step must be
- NO + O2 → NO3
- N2O2 + O2 → 2NO2
- N2O2 → 2NO
- NO2 + NO → N2O3