Question

Which among the following compounds is most soluble in water?

• A. Ethanol
• B. Ethane
• C. Phenol
• D. Ethylene glycol

Answer 1

The Correct Option is D

To determine which compound is most soluble in water, we need to consider the molecular structure and the ability to form hydrogen bonds with water. Compounds that engage in hydrogen bonding are generally more soluble. 

1. Ethanol (C₂H₅OH): Contains an -OH group capable of hydrogen bonding, making it somewhat soluble.
2. Ethane (C₂H₆): Nonpolar molecule with no hydrogen bonding capability, resulting in low solubility.
3. Phenol (C₆H₅OH): Contains an -OH group but is less soluble due to the large nonpolar benzene ring.
4. Ethylene glycol (C₂H₄(OH)₂): Contains two -OH groups, allowing for extensive hydrogen bonding, resulting in high solubility.

Among the given options, ethylene glycol is the most soluble in water due to its two hydroxyl groups that can form multiple hydrogen bonds with water, enhancing solubility.

Answer 2

Ethylene glycol (C₂H₆O₂) is highly soluble in water due to its ability to form hydrogen bonds with water molecules. The molecule contains two hydroxyl groups (–OH) that can interact with water molecules through hydrogen bonding. This interaction allows ethylene glycol to dissolve easily in water, as the hydrogen bonds between the –OH groups and water molecules help to break apart the water structure and integrate the ethylene glycol into the solution.

The presence of these hydroxyl groups makes ethylene glycol a polar molecule, which enhances its ability to interact with the polar water molecules. This is in contrast to non-polar substances, which are typically less soluble in water. Ethylene glycol’s high solubility in water is one of the reasons it is commonly used as an antifreeze and in various industrial applications, where its ability to mix with water is important.