1. Why does Huck assume Tom Sawyer's identity?
It’s easy and comfortable being Tom. He knows him so well that it was easy to take on the role of a close friend. He was also assumed to be Tom by Tom’s aunt and uncle, and it was going to make it easier to save Jim, so why not?

2. What happens when Tom appears on the scene?
Huck catches him before he reached the house. They then devise a plan to get out of there but not without a little bit of fun of course.

3. What's the difference between Tom's plan for freeing Jim and Huck's?
Huck is serious about freeing Jim but Tom kind of treats it like a game. Tom is in it for the adventure.

4. How does Huck change when Tom comes?
Huck let’s Tom take the reigns and gives him control of the situation.