"whose" equates with "of whom/which"


As far as I know that “whose” equates with “of whom/which”
So my question is as follows: can I say
whose car is that? = car of whom is that?/ car of which is that?
Whose is that car? = Is that car of whom?/ Is that car of which?

I know that “whose” is a possessive, but what part of speech it is in those sentences above?

It would be greatly appreciated

“whose” is a possessive adjective in “Whose car is that?” and a pronoun in “Whose is that car?”. However, the latter sentence doesn’t sound natural to me.
And no, you can’t say “car of whom is that?” (“car of which” would be even more incorrect, since “which” refers to things or facts, not to humans).
I hope this helps,

Thank you so much indeed, Michele

You are welcome!

“Whose is that car?” is fine, although less common than “whose car is that?”.

Ok, thanks.