free radical substitution

Question 1

essential condition from free radical substitution

Answer 1

UV light- provides enough energy to break a halogen bond.

Question 2

Initiation equation

Answer 2

must begin with halogen e.g chlorine
Alkanes are non-polar molecules with no areas of positive or negative charge.
UV provies energy to break Cl2 molecule into 2 Cl atoms with a unpaired electron.

Question 3

what is a free radical

Answer 3

an atom with an unpaired electron.

Question 4

Propagation equations

Answer 4

Cl. + CH4 —> .CH3 + HCl
.CH3 + Cl2—–> CH3Cl + Cl.
this process must be carefully controlled as it is very explosive
each reaction is very exothermic
they involve a free radical and generate a new free radical

Question 5

Termination equations

Answer 5

two alkyl radicals e.g .CH3 +.CH3 —->C2H6
two halo resdicals e.g. Cl. + Cl. —-> Cl2
one halo and one alkyl radical e.g. .CH3 + Cl. —-> CH3Cl