I have a question regarding the radical halogention of alkanes; in the chain propagation portion when R’ + Cl2 = RCl + Cl’, why doesn’t the R’simply attach to the extra Cl^- from chain initiation? (It does, but slowly because of very low concentration. - GS). In chain initiation, Cl2 = 2 Cl. In the first part of chain propagation, one Cl is used but there is no mention of what happens to the other. (Same thing. Both atoms are identical. - GS). In other words, is the second part of chain propagation (R’ + Cl2 = RCl + Cl) used to initiation the breaking of a Cl2 bond and continue the reaction? (It does break the Cl-Cl bond, but it is called propagation rather than initiation. - GS). So if there is no irradiation by light or heat, will the Cl2 bond not break and propagation won’t occur? (Light or temperature are not needed for propagation because of the highly energetic carbon-centered free radical. - GS). But on your powerpoint, you stated for initiation to occur, it requires light or heat. I don’t understand how propagation can then occur

without the initial breaking of the Cl2? (It can not. Propagation must be preceded by initiation. - GS).