MCQs – Chemical Kinetics
1. The unit of rate constant for a first-order reaction is:
a) mol L⁻¹ s⁻¹
b) s⁻¹
c) L mol⁻¹ s⁻¹
d) mol² L⁻² s⁻¹
2. For a zero-order reaction, the rate depends on:
a) Concentration of reactants
b) Temperature only
c) Rate constant only
d) Both concentration and rate constant
3. If half-life of a first-order reaction is 20 minutes, the rate constant is:
a) 0.0347 min⁻¹
b) 0.693 min⁻¹
c) 0.020 min⁻¹
d) 0.050 min⁻¹
4. In the Arrhenius equation k=Ae−Ea/RTk = A e^{-Ea/RT}k=Ae−Ea/RT, the slope of lnk\ln klnk vs 1T\frac{1}{T}T1 is:
a) −Ea/R-Ea/R−Ea/R
b) Ea/REa/REa/R
c) R/EaR/EaR/Ea
d) −R/Ea-R/Ea−R/Ea
5. For a reaction A→BA \to BA→B, the rate of disappearance of A is 0.03 mol L⁻¹ s⁻¹. The rate of appearance of B is:
a) 0.03 mol L⁻¹ s⁻¹
b) 0.015 mol L⁻¹ s⁻¹
c) 0.06 mol L⁻¹ s⁻¹
d) Zero
6. Which order of reaction has half-life independent of initial concentration?
a) Zero order
b) First order
c) Second order
d) Third order
7. A reaction is first order in A and zero order in B. The rate law is:
a) Rate = k[A][B]
b) Rate = k[A]
c) Rate = k[B]
d) Rate = k[A][B]⁰
8. A plot of [A][A][A] vs time is linear for:
a) Zero order reaction
b) First order reaction
c) Second order reaction
d) Third order reaction
9. The activation energy of a reaction is 50 kJ mol⁻¹. If temperature increases, rate constant will:
a) Increase
b) Decrease
c) Remain constant
d) Become zero
10. The rate constant of a reaction doubles when temperature is increased by 10°C. This is known as:
a) Van’t Hoff’s rule
b) Arrhenius rule
c) Rate law
d) Lindemann rule
11. The half-life of a zero-order reaction is given by:
a) t1/2=0.693kt_{1/2} = \dfrac{0.693}{k}t1/2=k0.693
b) t1/2=[A]02kt_{1/2} = \dfrac{[A]_0}{2k}t1/2=2k[A]0
c) t1/2=1k[A]0t_{1/2} = \dfrac{1}{k[A]_0}t1/2=k[A]01
d) t1/2=k[A]0t_{1/2} = k[A]_0t1/2=k[A]0
12. The order of a reaction can be determined by:
a) Molecularity
b) Balanced chemical equation
c) Experimental data only
d) Thermodynamics
13. In a chemical reaction, doubling the concentration of reactant doubles the rate. The order is:
a) Zero
b) One
c) Two
d) Three
14. The rate constant of a first-order reaction is 0.231 min⁻¹. The half-life is:
a) 3 min
b) 10 min
c) 30 min
d) 300 min
15. Molecularity of a reaction can be:
a) Zero
b) Fractional
c) Whole number only
d) Infinite
16. For a first-order reaction, the graph between ln[A]\ln [A]ln[A] and time is:
a) Straight line, positive slope
b) Straight line, negative slope
c) Curve increasing
d) Curve decreasing
17. In a reaction, rate = k[A]²[B], the overall order is:
a) 1
b) 2
c) 3
d) 0
18. Temperature dependence of rate constant is expressed by:
a) Rate law
b) Arrhenius equation
c) Collision theory
d) Gibbs free energy
19. If the rate of reaction does not change with concentration, the order is:
a) Zero
b) First
c) Second
d) Infinite
20. In pseudo-first order reactions:
a) Both reactants are first order
b) Both are zero order
c) One reactant is in large excess
d) Reaction is always second order
✅ Answer Key
- b
- c
- a
- a
- a
- b
- b (or d, since [B]⁰ = 1)
- a
- a
- a
- b
- c
- b
- b
- c
- b
- c
- b
- a
- c
Sarvan sir- Chemistry For All 