Solution:
Step 1
The iodination of methane can be carried out by the following ways:-
I2 + CH3 I-CH3 + I .
Mechanism:-
1)Initiation:-
This step involves the generation of active species (free radical)
2) Propagation:-
This process involves the growth of a polymer chain by successive addition of monomers during propagation can be represented as follows:-
The value of ΔH° for each step in the formation of iodination of methane can be calculate as,
For breaking I-I , ΔH° = +151 KJ/mole (+ 36 Kcal/mole)
For breaking H-CH3, ΔH° = +435 KJ/mole (+ 104 Kcal/mole)
For making H-I , ΔH° = -297 KJ/Mole (-71 KCal/mole)
Total ΔH° = +138 KJ/mole (+ 33Kcal/mole)
To break I-I ΔH° = +151 KJ/mole (+36 Kcal/mole)
To make I-CH3 ΔH° = -234 KJ/mole (-56Kcal/mole)
Total ΔH° = -83 KJ/mole (-20 Kcal/mole)
