Hva vs det/den som
How interchangeable are these? Of course as a question word only Hva is valid but what about sentences like "det er det som jeg har" and "det er hva jeg har" (couldn't think of any real examples)
Are they both correct/interchangeable here? If not what is the difference and how do you know when to use which?
They are not interchangeable, except in some special cases.
"Hva" is for questions (mostly). "Den/det som " -the one that, the thing that. The most common way of saying "what I have" is probably "det jeg har".