https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
It happens to the best of us.
(My guess is that we still need a few thousand years to answer these questions. We still don't understand too may details about Carbon based life. I'm not very optimistic.)
We [1] can eat things with Nitrogen, so I expect a competing form to be completely eaten if they are less effecient.
I don't know enough about Boron chemistry, but if there were enough of them we will eat them too, unles they eat us first.
The first stages of living things are probably very ineficient. If you need a year to make a viable copy, a previus life form will probably eat you before that. I think that two independent origins of life in tha same planet are impossible.
[1] If you include bacteria and archea in "we". And even we (humans) can eat some compound with nitrogen, in particular proteins that mix carbon and nitrogen.
Boron nitride is weirdly analogous (indeed, isoelectronic) to carbon in that there's a graphite-like form (hexagonal BN) and a diamond-like form (cubic BN).
One thing that would hold back BN life is that by themselves B and N form more stable compounds than carbon does. Nitrogen in particular forms molecular nitrogen, which is annoyingly tightly bound.
Look at silicon on the periodic table. All of the things that make carbon great, basically silicon has almost exactly, except it needs a high temperature for most of those properties to be expressible.
That teacher didn’t know what he was talking about. Ridiculing a student for questions is such detestable behavior. The silliest questions can end up being the most insightful. I really despise teachers like that.
Here is a paper all about how your question was actually wonderful.
Your linked paper points out that the only viable solvent that supports a large variety of silicon chemistry is sulphuric acid, and even then it would need to be very poor in oxygen since silicon-oxygen bonds are so strong it ends up being much more strongly preferred over si-si bonds.
It makes for an interesting conversation, but I can't imagine spending an entire class going over what amounts to a massive distraction from the lesson plan.
All that's left is going to amount to an effectively dismissive answer, I suppose (though I agree that teachers who are intentionally dismissive are doing it wrong).
I’m thinking of Venus. That sort of environment would satisfy all criteria and would also start to get into the temperature ranges that would make Si-Si bonds possible.
That would at-least bracket the types of planets and their history to a useful extent.
In a lab, it makes for a good solvent, but any place that has sulphuric acid will have both water and oxygen.
Venus, notably, has little to none of both. What free oxygen that does exist is from CO2 and CO breaking down in the atmosphere from the intense and extended venusian day. Most of the sulphur on Venus is sulphur dioxide (a tiny percentage of the atmosphere), and water vapor is a measly 20ppm.
Even if all of that water was sulphuric acid (which it may well be), there's simply not enough of it staying still long enough to form the repeating patterns of chemistry that might reasonably be called life.