American Chemical Society (ACS) Chemistry Test 2025 – 400 Free Practice Questions to Pass the Exam

The state of solubility for carbonates in water is characterized by the general rule that most carbonates are insoluble in water, with specific exceptions. Typically, carbonates of alkali metals such as lithium, sodium, potassium, rubidium, and cesium are soluble in water. This is due to the strong ionic bonds in the carbonate ion combined with the solvation ability of these alkali metal cations, which destabilizes the solid lattice structure of the carbonates, allowing them to dissolve.

In contrast, carbonates of other metals, particularly transition metals and heavy metals, tend to be insoluble or only sparingly soluble in water. Therefore, the correct understanding is that while most carbonates do not dissolve significantly in water, alkali metal carbonates do dissolve readily, marking them as the primary exceptions. This specific solubility behavior highlights the necessity of knowing not only general solubility rules but also recognizing the exceptions governed by the nature of the cation involved.