If you only have 5 - 10 minutes, ask for an email to follow up with. I usually give out my email address if a candidate is doing well. If you are going to join the team, you don't want to go in with wrong expectations.

Here are questions that I like to ask:

1. What are you biggest pain points?

2. If there was one thing you could change about the company, what would it be?

This is really great - I have been doing some hiring recently and it would really help me if candidates asked more questions so that I can talk about their interests.

I doubt 5 or 10 minutes is enough time to ask/answer more than one or two questions...