Question

what is the structure of 2 - bromo - 5 - hydroxyheptanal?

Explanation:

Step1: Analyze the name

The name 2 - bromo - 5 - hydroxyheptanal indicates a 7 - carbon (hept -) aldehyde ( - al) with a bromine (Br) atom at the 2nd carbon and a hydroxyl (OH) group at the 5th carbon.

Step2: Check the aldehyde group position

The aldehyde group ( - CHO) should be at the end of the carbon - chain, which is the 1st carbon.

Step3: Check the bromine and hydroxyl positions

The bromine should be on the 2nd carbon and the hydroxyl on the 5th carbon.
Looking at the options:
The correct structure has the form $CH_3CH_2CH(Br)CH_2CH(OH)CH_2CHO$. This corresponds to the second option where the Br is on the 2nd carbon and OH is on the 5th carbon of the heptanal chain.

Answer:

The second option: $CH_3CH_2CH(Br)CH_2CH(OH)CH_2CHO$