This piano sonata is in 5 part rondo form (ABACA). The A section is in ronded binary form, from meausures 1-20. It starts off very quiet, but then the dynamics changes to forte, emphasizing the expository section once again. The first A section ends on a PAC in D.
The B section lasts from m. 21-40, and modulates to the parallel minor. The motive changes, as well as dynamic use, but it's still in rounded binary form.. It feels very unstable in this section (well actually, really only in measures 21-28), feeling like measure 28 ends on a PAC in f major. Anyway, the B section ends on a pac in d minor.
The exact A section returns again, meaning the key changes back to D major. The A section lasts from measures 41-60.
A new alternative section is heard (the C section), and is from m. 61-80 in rounded binary form again.. It sounds like its in G major. It also sounds very jumpy and hurried, playing around with the rhythm and running 16th notes, so the motive is very differen t from the a section. It doesn't have as clear of a structure as the A section.
Measures 81-93 seem like a retransition back to the A section, with a very terminative feeling from 88-92.
The A section returns for the last time, this time with no repeat signs because the bass line is now playing these running 16th notes, which help create tension and makes it feel like an ending section. It ends on a PAC in the original key.
This piece seems very spirited and whimsical with many suprising leaps and mood changes, so the term innocentemente is appropriate. Good word. Good job Haydn.