At the end of nearly every interview, interviewers will turn the tables on you and ask if you have any questions for them. The correct answer to that question is always a resounding "YES!!" Not having a prepared list of questions ready for the employer will make it appear that you're not interested in the position or the company, so you MUST have a list ready. This is another place where the research you should have done on the company will come in handy. This research will help you to come up with some targeted questions to ask the employer. Here are a few possibilities to get you started:
The interview is NOT the appropriate place to ask about salary and benefits. Questions about that can come AFTER you've been extended an offer, but first, you have to get the offer!