For cyclohexane, you could use either and it wouldn't matter. If it's not cyclic and just a plain alkane, say propane, Br/hv attacks the most substituted C, while Cl/hv attacks both the most substituted (middle C) and least substituted (side C's).
For cyclohexane, you could use either and it wouldn't matter. If it's not cyclic and just a plain alkane, say propane, Br/hv attacks the most substituted C, while Cl/hv attacks both the most substituted (middle C) and least substituted (side C's).