The acetoxy group in ortho position in phenyl acetate does interact with the phenyl moiety in the molecule via resonance.
This detailed interaction of the acetoxy group in ortho position in phenyl acetate with the phenyl moiety in the molecule via resonance is shown in the image attached.
This interaction is made possible because the oxygen atom of the acetoxy group has lone pairs of electrons that are suitably positioned to interact with the ring via resonance.
The moles of ammonium nitrate needed to dissolve 0.35 moles The moles of water that will react is 0.35 moles as due to ratio so mass of water will be 0.35 x 18=6.3g MASS OF WATER WILL BE 6.3 g