Many pharmaceuticals are highly specific in the sense that they are active only if they have the correct chirality. In some cases, a compound with the wrong chirality might be lethal. It is vitally important to be able to distinguish molecules with different chiralities. A bromoalkane is formed from an alkane when a bromine atom replaces a hydrogen atom. Decide whether the bromoalkanes

(a) CH₃CH₂CHBrCH₃ and 

(b) CH₃CHBrCH₃ are chiral.

PLAN Identify carbon atoms as chiral if they have four different groups attached.