In composition, the purpose of exposition is to explain something, and you see it when characters reveal facts about place, setting, and plot involvement. In a dramatic play, the exposition takes place at the beginning of the work — to set the tone, introduce characters and their relationships, establish the setting, and offer other information to help you understand the rest of the play.
Act I: Scene 1 of Othello opens with a heated conversation between Iago and Roderigo that catches our interest — we realize that Iago is trying to persuade Roderigo to take part in a plan to destroy Othello. The exposition in this scene
- Sheds light on Iago's basic character, which is treacherous, vindictive, and manipulative
- Unveils the primary conflict of the play: Iago, who claims to have been passed over for promotion by Othello, harbors deep resentment and hatred toward his boss.
- Establishes two major themes: Appearance is not the same as reality; and racism (Othello, a Moor, is black)
At the end of Act 1: Scene 1, you also learn that Othello
- Is a highly honorable man
- Has eloped with Brabantio's daughter, Desdemona
- Is the top general whom Venice seeks for its defense in the war against the Turks
All of the information you learn about the characters in this first act adds to the drama and action that culminates in tragedy at the end of the play.