Free download in PDF Class 12 Chemistry Chapter 4 Chemical Kinetics Short Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries./p>
If the initial concentration of the reactant is doubled, the time for half reaction is also doubled. Then the order of the reaction is
4
The correct difference between first and second order reactions is that
A
A first order reaction can be catalysed; a second order reaction cannot be catalysed
B
The half life of a first order reaction does not depend on [A0]; the half life of a second order reaction does depend on [A0]
C
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
D
The rate of a first order reaction does depend on reactant concentrations; the rate of a second order reaction does not depend on reactant concentrations
6
When the concentration of reactant molecules is increased, the rate of reaction increases. The best explanation is: As the reactant concentration increases
A
the average kinetic energy of molecules increases
Answer: the frequency of molecular collisions increases
7
Which of the following statements are true?
(1) Reactions with more negative values of Go are spontaneous and proceed at a higher rate than those with less negative values of Go.
(2) The activation energy, Ea, is usually about the same as E for a reaction.
(3) The activation energy for a reaction does not change significantly as temperature changes.
(4) Reactions usually occur at faster rates at higher temperatures.
10
Which items correctly complete the following statment?
A catalyst can act in a chemical reaction to:
(I) increase the equilibrium constant.
(II) lower the activation energy.
(III) decrease E for the reaction.
(IV) provide a new path for the reaction.
11
Most reactions are more rapid at high temperatures than at low temperatures. This is consistent with:
(I) an increase in the activation energy with increasing temperature.
(II) an increase in the rate constant with increasing temperatures.
(III) an increase in the percentate of "high energy" collisions with increasing temperature.
12
What is the activation energy (in kJ) of a reaction whose rate constant increases by a factor of 100 upon increasing the temperature from 300 K to 360 K?
13
Suppose the activation energy of a certain reaction is 250 kJ/mol. If the rate constant at T1 = 300 K is k1 and the rate constant at T2 = 320 K is k2, then the reaction is __ times faster at 320 K than at 300 K. (Hint: Solve for k2/k1.)
15
If reaction A has an activation energy of 250 kJ and reaction B has an activation energy of 100 kJ, which of the following statements must be correct?
A
If reaction A is exothermic and reaction B is endothermic then reaction A is favored kinetically
B
At the same temperature the rate of reaction B is greater than the rate of reaction A
C
The energy of reaction A must be greater than the energy of reaction B
D
The energy of reaction B must be greater than the energy of reaction A
Answer:At the same temperature the rate of reaction B is greater than the rate of reaction A
16
Given that a reaction absorbs energy and has an activation energy of 50 kJ/mol, which of the following statements are correct? (Hint: Draw the potential energy diagram.)
(1) The reverse reaction has an activation energy equal to 50 kJ/mol.
(2) The reverse reaction has an activation energy less than 50 kJ/mol.
(3) The reverse reaction has an activation energy greater than 50 kJ/mol.
(4) The change in internal energy is less than zero.
(5) The change in internal energy is greater than zero.
