question on or about
What is the difference between two structures: "a question about something" and "a question on sth"? Are they synonymous or not?

Question

Answer

I think the answer to your question is, about is used to indicate information in general or relating to something and on is used to be more specific with regard to something.
An example might be:
I have a question about dogs.  (General case)
I have a question on the care and maintenance of dogs.  (Specific case)