Which tonal relationship typically characterizes the second movement of a sonata in Sonata Allegro form?

The second movement of a sonata in Sonata Allegro form typically maintains the same key as the first movement, often serving as a contrasting theme within the larger structure of the work. This consistency in key helps to unify the piece while allowing for different emotional expressions or themes to be explored. While other tonal relationships, such as relative minor or dominant key, could appear in various forms and contexts, they are not the standard characteristic of the second movement in Sonata Allegro form. The preservation of the original key helps to uphold the integrity of the sonata's overall tonal framework, allowing for a cohesive listening experience. In many classical compositions, this adherence to the original key is a hallmark of sonata design, where the second movement often exhibits thematic and emotional diversities while remaining anchored in the tonal foundation established by the first movement.