When is it not appropriate to use data from Wikipedia for a research task?

When you need facts.  Wikipedia does have a lot of information, but it is only that (information).  Information found on wikipedia may contain more opinions rather than facts and opinions can be bias. If you need facts, then this is not the appropriate place to get your facts from.  It may however, provide you with other sources that you can refer to.

Wikipedia is just a general information without the authentic proof  and anyone could make changes .