Which compounds are considered insoluble except for specific exceptions?

Insolubility rules in chemistry help predict whether a compound will dissolve in water. The correct answer pertains to oxides and hydroxides, which often are considered insoluble except for select exceptions. Most metal oxides and hydroxides do not dissolve well in water, making them generally insoluble. However, there are notable exceptions; for instance, the hydroxides of alkali metals like sodium and potassium are soluble, as well as some alkaline earth metal hydroxides like calcium hydroxide.

In contrast, the other groups of compounds listed exhibit different behaviors. Nitrates and acetates are typically soluble in water, which means they do not fit the criteria of being insoluble with exceptions. Chlorides and bromides are generally soluble, although there are exceptions (such as silver chloride), but these exceptions do not constitute a category of primarily insoluble compounds. Sulfates also tend to be soluble with some exceptions, notably barium sulfate and lead sulfate, but this does not define them as primarily insoluble. Therefore, the focus on oxides and hydroxides aligns with the characteristics of compounds largely considered insoluble except in specific cases.