What happens when your company gets acquired?

The company I'm currently employed at may get acquired by either a private equity firm or a tech firm. I had a few doubts that I was hoping someone on Grapevine might be able to answer.

1. What happens to my unvested RSUs if my company is acquired? It's already listed on the market.
2. What's the difference between a private equity acquisition and a tech firm acquisition?
3. From the employee's perspective, what are the things I should be worried about?