Testing if Rank Data varies significantly from 0

#1
Hi, I've done a survey with an 11 point Likert scale (-5 to +5, with 0).There are 30 questions total in the survey, with ~800 responses.

I have graphed the median response for each survey question, but I am looking for a way to test which questions are 'significantly' different from 0 (a neutral response).

I was looking at Mann-Whitney U test, but that doesn't seem to make sense if I don't actually have 2 distributions of data (one is just 0). Is there another test that I could use?

Thanks,
Andrew