molodets, one can not approach the issue of gender in Russian that way (like in a Romance language) and a good way to look at it is in terms of soft/hard endings, but even that is not so strict.
It doesn't matter whether you say, "Чей это сок?", "Это чей сок?" or "Чей сок это?" - all three options are used and mean the same thing. But the first one is the most common one. And it doesn't sound any more weird than the English "Who are you talking to?" (as opposed to "To whom are you talking?") sounds to a Russian.
"This is", "These are", "Is this" and "Are these" - all of those phrases correspond to the same Russian pronoun "Это". There is also a demonstrative adjective "это" which modifies singular nouns of neuter gender, e.g. "это окно" = "this window". But we say "этот стол" ("this table" - masculine gender) and "эта стена" ("this wall" - feminine gender).
I know all of this, but this one really doesn’t make any sense to me. It’s the word order that’s messing me up. when you say «это стол», subject verb, cool, it works. if you say это чей сок? cool, it works as well. чей сок это, cool as well. but Чей это сок? this word order is weird as all hell. why would you separate “whose” from “juice”? it’s like your asking about это instead of juice.
I also find the word-order problematic, from an English-speaking point of view. Studying Romance languages doesn't help either, where equivalents to Это are often required to agree with the noun they're attached to.
Most of all, though, is the "logic" (not making fun of anyone here, just pointing out why I'm having a little problem here) is that the sentence more or less means "Whose juice is this unknown thing?" when you know perfectly well it's juice. I'm getting used to the lack of agreement between это and everything else, it just seems a bit odd.
PS But even in French, there's an equivalent: c'est (an abbreviation of ce est) and ce sont:
C'est un homme, c'est un femme, ce sont des hommes, ce sont des femmes:
"He is a man, she is a woman, they are men, they are women".
Ce has a lot of uses in French. Like c'est du jus = "It is juice".
This is the second day in a row that my correct answers have been marked incorrect. I typed Чей это сок? and Duolingo said the correct answer is Чей это сок? Yesterday it said my 92 day streak was in peril when I quit after numerous examples of the preceding. Why keep hitting my head on the wall? Is there a Duolingo staff person monitoring this? Есть техническая проблема?
Even if there were a staff person monitoring your comment what could they do about it? You haven't bothered to copy and paste your answer. So what can anyone do about your complaint but wonder why you are the only person experiencing your totally, completely correct answer being rejected multiple times on this example?