There are a number of different passages that you could select that would make excellent subjects of analysis. You might like to go for the opening of Chapter 37, which is the first chapter of the second section of the novel, where Pi finds himself in a lifeboat as the ship sinks and chaos reigns around him. There are a number of literary terms in this section that you could identify and analyse easily, such as the way in which the ship sinks with a sound like a "monstrous metallic burp." This simile also uses alliteration in the repetition of the "m" sound for extra emphasis.
You also might like to consider the way in which Pi uses a series of metaphors to describe his family members, such as when he comparaes his mother to a "tender guardian angel of wisdom." Consider as well the panic in Pi's voice and how he ironically appeals and tries to encourage Richard Parker to swim towards him, clearly not thinking through the logistics of having a tiger on the same boat as him.