Oxidation Numbers and Structures:

• H2SO5: The sum of oxidation numbers in a neutral compound is 0. Since hydrogen has an oxidation state of +1 and oxygen usually has an oxidation state of -2, we can set up the equation: 2x+(−2×5)=02x+(−2×5)=0. Solving for xx, we get x=+5x=+5. Therefore, sulfur has an oxidation state of +5 in H2SO5. The structure of H2SO5 can be suggested as a peroxysulfuric acid, also known as persulfuric acid (H2SO5H2SO5).
• Cr2O2: The sum of oxidation numbers in a neutral compound is 0. Considering oxygen usually has an oxidation state of -2, we can set up the equation: (2×x)+(2×(−2))=0(2×x)+(2×(−2))=0. Solving for xx, we get x=+2x=+2. Therefore, chromium has an oxidation state of +2 in Cr2O2. However, the compound Cr2O2 does not exist. A possible fallacy in the compound name could be due to misrepresentation or an incorrectly written chemical formula.
• NOT: The term "NOT" does not correspond to a known chemical compound. Therefore, no oxidation numbers or structures can be assigned.

Formulas for Compounds:

• (a) Mercury (II) chloride: HgCl2HgCl2
• (b) Nickel (II) sulphate: NiSO4NiSO4
• (c) Tin (IV) oxide: SnO2SnO2
• (d) Thallium: Thallium can form various compounds, so a specific formula cannot be given without additional information.

Substances with Variable Oxidation States for Carbon and Nitrogen:

• Carbon: Carbon can exhibit oxidation states from -4 to +4 in compounds such as methane (CH4CH4), carbon monoxide (COCO), carbon dioxide (CO2CO2), and formaldehyde (H2COH2CO).
• Nitrogen: Nitrogen can exhibit oxidation states from -3 to +5 in compounds such as ammonia (NH3NH3), nitric acid (HNO3HNO3), nitrogen gas (N2N2), and ammonium chloride (NH4ClNH4Cl).

Role of Sulphur Dioxide, Hydrogen Peroxide, Ozone, and Nitric Acid as Oxidants:

• Sulphur dioxide (SO2SO2) and hydrogen peroxide (H2O2H2O2) can act as both oxidizing and reducing agents because they can undergo oxidation and reduction themselves. Ozone (O3O3) and nitric acid (HNO3HNO3) primarily act as oxidants because they have high oxidation potentials and readily donate oxygen atoms or electrons to other substances.

Instability of AgF2 and Its Strong Oxidizing Property:

• AgF2 is unstable because silver typically forms compounds with a +1 oxidation state, not +2. If formed, AgF2 would have a highly positive silver ion and highly negative fluoride ions, making it an extremely unstable compound. However, if it were to exist, AgF2 would likely act as a strong oxidizing agent because of the high electronegativity of fluorine and the high positive charge on the silver ion.