what/which nationality are you

If you ask [which] it usually indicates that there's something to choose from.
For example: [Which is your nationality, British or French?]
And you answer either [British] or [French]. Or if you are not, you could answer: [Neither. I am Italian.]

But if you ask [what] they assume you don't know anything at all and the answer could be anything. This one is a more straight forward question: [What is your nationality?] And you just answer: [I am Italian.]

What nationality are you? = What is your nationality? We are human being so which is wrong.

Which always refer to non human item 死物

Whichbag do you like?
Which bag is yours?
Which is your bag?
Which one do you like to have?

This is the bag, which Ｉbought last week.
This is the bag, which I like the best.

What nationality are you? = What is your nationality?
= 你的國藉是甚麼?


你將 which nationality are you? 變做中文,就會
覺得好奇怪