I am wondering is following question correct:
Is it what was supposed to be done here?
Thanks in advance.
Yes, it is indeed correct.
The subject of the sentence is "it," the verb "is," and the predicate "what was supposed to be done here."
It is like "is it the best job that could have been done here?" except the predicate is a noun clause with an interrogate.
hope it makes sense! :^)