Why would a chromium solid that is more soluble be less satisfactory for disposal? PLEASE HELP?

Answer 1

Chromium is really really really toxic. It is definitely something we do not want in our ground water. So, there a laws that against dumping chromium (especially dissolved) down the drain. The chromium you might see on shiny hubcaps does not dissolve easily, so that is less of a concern than chromium solutions in the lab going down the drain.