What is noni doing here?

I’m curious about this sentence, I wonder if someone could help me know what it means:

子供が一人で旅行するなんて、どんな危険が待っているかもしれないのに。

1) Could you translate this into English?

2) What is the exact function of のに here? Is it functioning as a question particle?

Thank you in advance for your answers!

no ni / のに means "though." For examp;e,
彼は来ると言ったのに、来なかった。
Kare ha kuru to itta no ni, konakatta.
Though he said he would come, he did not come.

Ordinarily no ni comes in the middle of the sentence, but colloquially it sometimes shows up at the end, like in your sentence
子供が一人で旅行するなんて、どんな危険が待っているかもしれないのに。
If the speaker was organizing their thoughts a little more clearly before speaking, this would probably be
どんな危険が待っているかもしれないのに、子供が一人で旅行するなんて
meaning
"Even though it could be incredibly dangerous, a child travelling alone..."

The sentence itself, as you can see, is omitting something, but in this case it's pretty easy to infer. なんて implies that the speaker thinks the idea of a child traveling alone is outrageous or illogical, so the overall meaning here is "A child traveling alone, without concern to how dangerous that is, is crazy."