The intermolecular forces in ethyl acetone are dispersion and hydrogen bonding and acetone has the same
Yeah, so the thing with solubility is that the highest determining factor for it is polarity. Hydrogen bonding is also important to consider, but dispersion forces are not. Dispersion forces are really weak, remember, so if something is polar, the energy for that is going to dominate in something dissolving. The other thing with hydrogen bonding, is you need to figure out if something is a hydrogen bonding donor or acceptor, or both. Water, for example, is both a hydrogen bond donor, and a hydrogen bond acceptor. Methanol is also both a hydrogen bond donor and acceptor. Ammonium, however, is only a hydrogen bond donor, and not a hydrogen bond acceptor. The reasons for these are to be a hydrogen bond donor, you need a hydrogen attached to your strongly electronegative atom (usually O and N). To be a hydrogen bond acceptor, you need a lone pair attached instead (which ammonium does not have). As another example, if you look at
this molecule (which has a lone pair on the nitrogen, not shown), it is not a hydrogen bond donor, because it doesn't have a hydrogen attached to the nitrogen. It is, however, a nitrogen bond acceptor.
Knowing this now, would you still say ethyl acetate is going to be most soluble in acetone, or would you change your mind, and why?