11. Radical Reactions

In the following molecule, which of the labeled hydrogens ($A$, $B$, $C$, or $D$) is most easily abstracted in a free radical bromination reaction? (Assume the hydrogens are: $A$ = methyl hydrogen, $B$ = primary hydrogen, $C$ = secondary hydrogen, $D$ = tertiary hydrogen.)

Consider this step in a radical reaction: $\mathrm{Cl}\cdot$ + ${\mathrm{CH}}_4$ → ${\mathrm{CH}}_3\cdot$ + ${\mathrm{HCl}}_{\mathrm{}}$. What type of step is this in the radical chain mechanism?

When the compound $C_6{H}_5\mathrm{CH}{2}_2\mathrm{CH}{3}_3$ (ethylbenzene) is treated with n-bromosuccinimide (NBS) in the presence of light, which of the following is the major product?

Show how the following compounds could be prepared from 2-methylpropane:

b. 2-methyl-1-propene

In the radical bromination of $2_{\text{-methylbutane}}$, which hydrogen atom is most likely to be abstracted by a bromine radical?