What types of species may form when substances dissolve in water?

When substances dissolve in water, they can dissociate into various types of species, primarily molecules and ions. Many ionic compounds, such as sodium chloride, will dissociate into their respective ions when they dissolve, producing positive and negative ions in the solution. This ion formation is a key feature of how electrolytes function in aqueous solutions.

Additionally, certain covalent substances can also dissolve in water without dissociating into ions. Many polar covalent molecules, like glucose, dissolve in water as intact molecules rather than breaking apart into ions. This ability to stay as whole molecules is significant in understanding solutions, particularly in biological contexts.

In contrast, nonpolar molecules typically do not dissolve well in water due to their incompatible interactions with the polar water molecules. Thus, the formation of only nonpolar molecules is not applicable when discussing solubility in water. Options that limit the dissolved species to just ions or only polar molecules also do not capture the complete picture of solubility in water. Overall, the most accurate representation of what can occur when substances dissolve in water is the presence of both molecules and ions.