Which one is water soluble?

The correct choice indicates that a polar solvent is water soluble. This is because water itself is a polar molecule, meaning it has a partial positive charge on one end and a partial negative charge on the other due to its bent shape and the difference in electronegativity between hydrogen and oxygen. Polar solvents interact favorably with water, allowing them to dissolve easily.

The dynamic of "like dissolving like" applies here; substances that are polar can effectively mix with water because their molecular structures allow for strong intermolecular forces, such as hydrogen bonding, to occur. This characteristic of polar solvents is essential in various chemical processes and applications in fire fighting, including the use of aqueous solutions for extinguishing certain types of fires.

While non-polar solvents do not interact well with water and tend to separate from it, organic solvents can be polar or non-polar depending on their structure. Acidic solvents refer more to the acidic nature of the solution rather than its solubility properties, making them less directly relevant to the concept of solubility in water. Thus, polar solvents are the most accurate representation of substances that are water soluble.