I'd suggest specifics if you can.
Can you tell me about the XYZ program? I'm particularly interested in X because of my experience or interest in Y, and I'd be eager to be a part of it. I know the website has some information, but I thought maybe you could provide a deeper view of the program. How do you view the program? Is it popular with students? Would you recommend it for someone interested in X?
Or, if you are feeling confident:
"I'm really interested in program X, but most of the information on the website is high level. Without being too forward, would it maybe be possible for me to speak to a student who has gone through the program? If not, could you provide any insight into X or Y?"
If you get a students name, great.
If this truly is an informal chat, use the time to address what you can about your background. "You know, I'm really interested in attending X, and I'm preparing my application. Any general advice you could provide?"
(They all say the same thing: "be yourself").
Or "I'd love to attend X, but I'm a little concerned that my GMAT score of XYZ may be a little low, or that my GPA of 1.25 from the Hawaiin School of Underwater BasketWeaving may not be competitive. I'm considering taking an additional course in statistics before applying, would you recommend this, and is there any value in doing so for my application? I wouldn't have a grade in time for the apps, but I'd be enrolled."
Alternatively you can take an alternate route:
"I'd love to attend X but my four years as a substitute janitor have left me with minimal leadership experience. Would you have any advice on what I can do to address this best?"
Or, approach with a specific question about the application: "For Q3, I'm eager to write about my experiences as a pilot for singapore airlines, for which I was unpaid, flying underpriveliged children to their new families in the US. It's not a professional experience, but I feel strongly about it, would you recommend I approach the question from this position?" (not a great question because they just say "write what you feel", so whatever)
Generally, try to ask insightful questions:
"I am married. Can you tell me about married life on campus? I'm concerned that your location on Pitcarin Island may not be best suited for her. Especially since virtually everyone on Pitcarin Island was put in jail for rape, and even had to build their own prison cause non existed on the island. (really, its true, look it up). What resources exist for married couples? Do you have many? Some schools have programs specifically tailored in this regard, do you?"
Or, less often used, and not particularly recommended:
"Look, if you don't accept me right now, I'm going to come down there and show you why my nickname in college was 'raging bull'. Get my drift?"