The A section of this piece goes from measures 1-33, and consists of four phrases that are each 8 measures long. Because each of these phrases end on a PAC, and because of the lack of antecedent and consequent activity, I would consider them to be a phrase group. The first phrase is in D Major, but there is a change in tonality to the key of A Major in the second phrase. The third phrase shifts back to D Major, and the fourth and final phrase is in A Major. The fact that the A section ends in a different key than it began makes this section open binary form. This section is definitely expository.
As far as structural phenomena goes, there is obviously the constant shifting in tonality between tonic and dominant throughout the A section. There is a change in density every time the four measures of sustained dotted half notes occur. The perfect authentic cadences are made to stand out with the use of quarter rests at every cadence.
The B section begins at measure 33 where the double barlines are, and ends at measure 49. There is another shift in tonality, and I am pretty sure it goes from the key of A to B. The B section is definitely developmental. There are several prominent uses of structural phenomena. There is a change in texture right away when the chords begin being played in the right hand and the left hand just holds out dotted half notes. We also see a huge change in range in the left hand. Throughout the A section the left hand never goes above a d above middle c. In the B section it goes all the way up to A sharp. After the formatta in measure 48, the same expository material from the A section returns again in the key of D Major, which makes this piece rounded binary form!