Question
Chemistry Question on reaction mechanism
The following reaction method 
is not suitable for the preparation of the corresponding haloarene products, due to high reactivity of halogen, when X is :
A
F
B
I
C
Cl
D
Br
Answer
F
Explanation
Solution
The reaction shown is a free radical halogenation reaction. This method is unsuitable for the preparation of fluoroarenes because of the high reactivity of fluorine. Fluorine is so reactive that it is difficult to control the reaction, leading to multiple substitutions. In this reaction, the free radical is formed by using the metal Fe in dark conditions. For the other halogens, the reaction can be controlled to obtain the corresponding haloarenes.