A Possible Reaction of Ethane with Chlorine Is Shown Below

Multiple Choice

A possible reaction of ethane with chlorine is shown below. $$\mathrm { CH } _ { 3 } \mathrm { CH } _ { 3 } + \mathrm { Cl } _ { 2 } \longrightarrow \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { Cl } + \mathrm { HCl }$$ This reaction could conceivably occur by the following chain mechanisms [1], [2], and [3]. The chain initiating step(s) is (are) _____. [1] $\mathrm { Cl } _ { 2 } \longrightarrow 2 \mathrm { Cl }^*$ .
[2] $\mathrm { Cl } ^* + \mathrm { CH } _ { 3 } \mathrm { CH } _ { 3 } \stackrel { \text { slow } } { \longrightarrow } \mathrm { HCl } + \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 }^*$ .
[3] $\mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } ^ { * } + \mathrm { Cl } _ { 2 } \stackrel { \text { fast } } { \longrightarrow } \mathrm { CH } _ { 3 } \mathrm { CH } _ { 2 } \mathrm { Cl } + \mathrm { Cl }^*$ .

A) Only [1]
B) Only [2]
C) Only [3]
D) Only [1] and [2]