In Sonata Allegro form, which section features Theme 1 in the tonic key and Theme 2 in the dominant key?

In Sonata Allegro form, the Exposition is the section where Theme 1 is presented in the tonic key, and Theme 2 is typically introduced in the dominant key. This structure sets the stage for the contrasts that are central to the form. The first theme establishes the home key, creating a sense of stability, while the second theme in the dominant key introduces tension and contrast. This duality captures the essence of the exposition’s role in establishing thematic material and tonal relationships which are further explored in the subsequent Development and Recapitulation sections.

The Development section often manipulates and transforms the themes, exploring various keys and even fragmenting the themes, but it does not present the themes in their initial tonic and dominant pairing as done in the Exposition. The Recapitulation revisits the themes, bringing Theme 1 back in the tonic key followed by Theme 2, now also in the tonic key, to create resolution. The Coda serves to conclude the piece, reinforcing the tonic key without introducing new themes or contrasting keys. Therefore, the Exposition is critical as it lays out the fundamental thematic and tonal framework that characterizes the entire sonata form.