What are the norms for declaring a question to be "off-topic" when it appears to relate to one of the categories outlined for on-topic questions and does not fall into the category of questions that are not allowed?
The question related to chemical solubility and precipitation in the following post was closed for being "off-topic." The question was asked by an apparent student of chemistry who sought to understand why the correct answer for the question was correct. The OP responded to questions that led to OP toward the answer and requests for additional input to improve the question.
Seeking clarification. Thank you.