CBSE Class 12 Chemistry Chapter 4 (Chemical Kinetics) By Homi Institute

1. CBSE Class 12 Chemistry
Chemical Kinetics

4. (colliding atoms)

6. Formic acid

9. Also, at what rate O2 will produce during this time?

10. Rate law or rate expression is the expression in
which reaction rate is given in terms of molar
concentration of reactants with each term raised to
some power, which may or may not be same as the
stoichiometric coefficient of the reacting species in
a balanced chemical equation.

11. Rate law for any reaction cannot be predicted by merely looking at the balanced chemical
equation, i.e., theoretically but must be determined experimentally.
Ex -

12. [𝐴]0

13. Answer – 2,0,2
Answer – ©
Answer - B

14. Answer - D

15. For Elementary reaction - The number of reacting species
(atoms, ions or molecules) taking part in an elementary
reaction, which must collide simultaneously in order to
bring about a chemical reaction is called molecularity of a
reaction.
For Complex reaction

17. First order gas phase reaction

20. Pseudo First Order Reaction

21. Temperature Dependence of the Rate of a Reaction
It has been found that for a chemical reaction with rise in temperature by 10°, the rate constant is
nearly doubled.
The temperature dependence of the rate of a
chemical reaction can be accurately explained by
Arrhenius equation.
k
measured in joules/mole

22. Activation energy is defined as the minimum
amount of extra energy required by a reacting
molecule to get converted into product. It can also
be described as the minimum amount of energy
needed to activate or energize molecules or atoms
so that they can undergo a chemical reaction or
transformation.
The peak of the curve corresponds to the most
probable kinetic energy, i.e., kinetic energy of
maximum fraction of molecules. There are
decreasing number of molecules with energies
higher or lower than this value.

23. When the temperature is raised, the
maximum of the curve moves to the
higher energy value and the curve
broadens out, i.e., spreads to the right
such that there is a greater proportion
of molecules with much higher
energies. The area under the curve
must be constant since total
probability must be one at all times.

24. high as 1010 times.
• A catalyst does not alter Gibbs energy,
ΔG of a reaction.
• It catalyses the spontaneous reactions
but does not catalyse non spontaneous
reactions.
Proper alignment
Proper alignment
Improper alignment
Improper alignment