Yes H is +1 and O is -1 is peroxides so these oxidation numbers are correct .
Nitrogen has +5 oxidation number in HNO3
Yes, since Al is underging an oxidation and Cl is undergoing reduction .
A reducing agent oxidizes during a oxidation -reduction reaction
6.88 × 10-7M
Ksp= 5.02 × 10-13
Ksp= [Hg22+] [Cl-]2
either equal to or greater then