In general they will ask you a bunch of questions to trip up anyone who might be too clever, but they can't ask about jury nullification directly (lest they give anyone else ideas). If you answer in the expected common sense way, and don't boast about your reasoning, it's going to be very hard for them to claim perjury.
And if they use "will", it's perfectly normal to wonder why one would ask such a strange question. It would totally read as "we're gonna find a case to test you on that teehee".
If they can't convince other jurors, no "harm" done. If they can, then perhaps the law is overkill. The judge seems to be overpowered here.
Arguably, the same reason judges should be allowed to remove jurors who admit their intent to convict an innocent defendant: jurors must apply the law impartially. The LII has a pretty decent primer on all this entails[1].
And almost all state laws require a jury to unanimously vote to convict, so empaneling a jury that has someone who will always acquit means that the jury's decision has been set from the beginning.
Personally, I live in a state that requires a unanimous vote to convict or acquit, and prohibits the judge from "poking at" a deadlocked jury[2]. In the few times I've been selected for a jury I haven't gone far enough to be asked if I would be impartial, and I'm glad because I've yet to decide where my personal ethics take me.
[1]: https://www.law.cornell.edu/constitution-conan/amendment-6/i...
In that sense, jury nullification can be impartial.
