Determine which molecule is most soluble in water,

• A. Nonane-2,5,7-triol
• B. Propane-1,2,3-triol
• C. Butane-1,2-diol
• D. Butanol

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of solubility in water, which largely depends on the molecule's ability to form hydrogen bonds with water molecules. Molecules with more hydroxyl (-OH) groups tend to be more soluble because these groups can form hydrogen bonds.
2. Step 2: Analyze the given molecules by counting the number of hydroxyl (-OH) groups in each. For example, Nonane-2,5,7-triol has three -OH groups, Propane-1,2,3-triol has three -OH groups, Butane-1,2-diol has two -OH groups, and Butanol has one -OH group.
3. Step 3: Consider the size of the hydrocarbon chain in each molecule. Longer hydrocarbon chains are more hydrophobic and reduce solubility in water, while shorter chains increase solubility.
4. Step 4: Compare the molecules by balancing the number of hydroxyl groups and the length of the hydrocarbon chain. Molecules with more -OH groups and shorter hydrocarbon chains will generally be more soluble in water.
5. Step 5: Conclude that Propane-1,2,3-triol is the most soluble because it has three hydroxyl groups and the shortest hydrocarbon chain among the options, maximizing hydrogen bonding and minimizing hydrophobic character.