# How do we assess solubilities of chromates, and ammonium salts?

Chromates tend to be insoluble; ammonium salts, like alkali metal salts, tend to be soluble. Of course, there are exceptions. $\text{ammonium tetraphenyl borate}$ is known to be quite insoluble. I cannot offer a simple way to remember them. I would try to remember your chemistry practicals..........