CBSE Class 12 Chemistry Chemical Kinetics Worksheet Set B

Chapter:4 (Chemical Kinetics)

State whether given statement is true or false.

1. The unit of K for first order reaction is molL^-1s^-1. ( )

2. The radioactive decay follows zero order kinetics. ( )

3. For r =k[A]²[B],the order of reaction is 3 ( )

4. For second order reaction unit of k is mol^-2L2s^-1. ( )

5. For a reaction order and molecularity are always same. ( )

6. Order of reaction is always a whole number whereas molecularity can be fractional. ( )

MCQ

1.The order of reaction for,r=k[A]²[B] is

(a). 1 b) 0 (c)2 (d) 3

2.A reaction 50% complete in 2 hours and 75% in 4 hours, the order of reaction will be

(a).0 b) 1 (c)2 (d) 3

3.For a reaction A+B → C,the rate law is given by r=k[A]^1/2[B]² the order of reaction is:

(a).0 b) 5/2 (c)2 (d) 3/2

4. What is the unit of K if rate ==K{A}2{B}

(a) s^-1 (b) mol L^-1 (c) mol^-2L²s^-1 (d) mol^-1Ls^-1

5.What is the molecularity of reaction for the following elementary reaction:

2A+B------------------------→C

(a) 1 (b) 2 (c) 3 (d) 0

6.What is the order for following photochemical reaction:

H₂+Cl₂------------→2HCl 

Important Questions for NCERT Class 12 Chemistry Chemical Kinetics

Question. For the reaction; 2N₂O₅ → 4NO₂ + O₂ rate and rate constant are 1.02 × 10^–4 and 3.4 × 10^–5 sec–1 respectively, then concentration of N₂O₅ at that time will be
(a) 1.732
(b) 3
(c) 1.02 × 10^–4
(d) 3.4 × 10⁵

Question. The given reaction,
2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄ is an example of
(a) third order reaction
(b) first order reaction
(c) second order reaction
(d) none of these.

Question. The rate constant for a first order reaction is 4.606 × 10^–3 s^–1. The time required to reduce 2.0 g of the reactant to 0.2 g is
(a) 100 s
(b) 200 s
(c) 500 s
(d) 1000 s 

Question. If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by
(a) t = 2.303/k
(b) t = 0.693/k
(c) t = 6.909/k
(d) t = 4.606/k

Question. A first order reaction has a rate constant of 2.303 × 10^–3 s^–1. The time required for 40 g of this reactant to reduce to 10 g will be [Given that log₁₀ 2 = 0.3010]
(a) 230.3 s
(b) 301 s
(c) 2000 s
(d) 602 s

Question. The correct difference between first and second order reactions is that
(a) the rate of a first-order reaction does not depend on reactant concentrations; the rate of a second-order reaction does depend on reactant concentrations
(b) the half-life of a first-order reaction does not depend on [A]0 ; the half-life of a second-order reaction does depend on [A]0
(c) a first-order reaction can be catalysed; a secondorder reaction cannot be catalysed
(d) the rate of a first-order reaction does depend on reactant concentrations; the rate of a secondorder reaction does not depend on reactant concentrations. 

Question. When initial concentration of the reactant is doubled, the half-life period of a zero order reaction
(a) is halved
(b) is doubled
(c) is tripled
(d) remains unchanged.

Question. A first order reaction has a specific reaction rate of 10^–2 sec^–1. How much time will it take for 20 g of the reactant to reduce to 5 g?
(a) 138.6 sec
(b) 346.5 sec
(c) 693.0 sec
(d) 238.6 sec 

Question. The rate of first-order reaction is 0.04 mol L^–1 s^–1 at 10 seconds and 0.03 mol L–1 s^–1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is
(a) 44.1 s
(b) 54.1 s
(c) 24.1 s
(d) 34.1 s

Question. When initial concentration of a reactant is doubled in a reaction, its half-life period is not affected. The order of the reaction is
(a) second
(b) more than zero but less than first
(c) zero
(d) first. 

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