Question

which of the pictured molecules is the most polar molecule? select one:

Explanation:

Step1: Recall polarity concept

Polarity is due to electronegativity differences and molecular - shape. Hydroxyl (-OH) groups are polar.

Step2: Analyze each molecule

The first molecule is an ether (diethyl - ether), has a non - polar hydrocarbon part and a slightly polar C - O bond. The second molecule is a long - chain alcohol (hexanol), has a long non - polar hydrocarbon chain but also a polar - OH group. The third molecule is a shorter - chain alcohol (propanol), has a non - polar hydrocarbon part and a polar - OH group. The fourth molecule is an alkane (butane), is non - polar as it has only C - C and C - H bonds with small electronegativity differences.

Step3: Compare polarities

Alcohols are more polar than ethers due to the presence of the highly polar O - H bond. Among the alcohols, the more compact propanol has a higher proportion of its molecule associated with the polar - OH group compared to the longer - chain hexanol.

Answer:

The third molecule (propanol)