Chemical Kinetics Questions and Answers | Chemistry MCQs for Class 12 with Answers Chemical Kinetics

Questions
1 MCQ on Chemical Kinetics This reaction follows first order kinetics. The rate constant at particular temperature is 2.303 × 10−2 hour−1 . The initial concentration of cyclopropane is 0.25M. What will be the concentration of cyclopropane after 1806 minutes? (log 2 = 0.3010)
A 0.125M
B 0.215M
C 0.25 × 2.303M
D 0.05M

Answer: 0.215M
2 For a first order reaction, the rate constant is 6.909 min-1.the time taken for 75% conversion in minutes is
A (3/2)log2
B (2/3)log2
C (3/2)log(3/4)
D (2/3)log(4/3)

Answer: (2/3)log2
3 In a first order reaction x → y ; if k is the rate constant and the initial concentration of the reactant x is 0.1M, then, the half life is

MCQ on Chemical Kinectics

A (a)
B (b)
C (c)
D (d)

Answer:(c)
4 Predict the rate law of the following reaction based on the data given below

2A + B → C + 3D

MCQ on Chemical Kinectics

A rate = k [ A]2 [B]
B rate = k [ A][B]2
C rate = k [ A][B]
D rate = k [ A]1/2 [B]3/2

Answer: rate = k [ A][B]2
5 Assertion: rate of reaction doubles when the concentration of the reactant is doubles if it is a first order reaction.

Reason: rate constant also doubles

A Both assertion and reason are true and reason is the correct explanation of assertion.
B Both assertion and reason are true but reason is not the correct explanation of assertion.
C Assertion is true but reason is false.
D Both assertion and reason are false.

Answer: Assertion is true but reason is false.
6 The rate constant of a reaction is 5.8 × 10−2 s−1 . The order of the reaction is
A First order
B zero order
C Second order
D Third order

Answer: First order
7

For the reaction  N2O5(g) → 2NO2 (g) + ½ O2(g), the value of rate of disappearance of N2O5 is given as 6.5 × 10-2 mol L-1 s-1. The rate of formation of NO2 and O2 is given  respectively as

A

( 3.25 × 10−2 mol L−1s−1 ) and (1.3 × 10−2 mol L−1s−1 )

B

(1.3 × 10−2 mol L−1s−1 ) and ( 3.25 × 10−2 mol L−1s−1 )

C

(1.3 × 10−1 mol L−1s−1 ) and ( 3.25 × 10−2 mol L−1s−1 )

D None of these

Answer:

(1.3 × 10−1 mol L−1s−1 ) and ( 3.25 × 10−2 mol L−1s−1 )

8 During the decomposition of H2O2 to give dioxygen, 48 g O2 is formed per minute at certain point of time. The rate of formation of water at this point is
A 0.75 mol min−1
B 1.5 mol min−1
C 2.25 mol min−1
D 3.0 mol min−1

Answer: 3.0 mol min−1
9 If the initial concentration of the reactant is doubled, the time for half reaction is also doubled. Then the order of the reaction is
A Zero
B one
C Fraction
D none

Answer: Zero
10 In a homogeneous reaction A →B + C + D , the initial pressure was P0 and after time t it was P. expression for rate constant in terms of P0, P and t will be

Chemical Kinetics

A (a)
B (b)
C (c)
D (c)

Answer: (a)
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