Final answer:
Isomeric alkyl magnesium bromides that react with water to yield propane are A. CH3CH2CH2MgBr (propylmagnesium bromide) and B. (CH3)2CHMgBr (isopropylmagnesium bromide). The other options do not give propane upon reaction with water.
Step-by-step explanation:
The student is asking for the structures of two isomeric alkyl magnesium bromide molecules that react with water to give propane. Alkyl magnesium bromides are reagents known as Grignard reagents, which means we are looking for isomers that can provide a propyl group upon reaction with water.
The correct answers from the options given are:
Option C is methylmagnesium bromide and option D is butylmagnesium bromide, neither of which gives propane upon reaction with water.