2. On planet Q the atmosphere is 10% oxygen and a few % of species of the element Z. The atmosphere also contains about 5% H₂O

Some facts about Z:

• Z exists in the atmosphere as the gaseous species H₄Z, ZO and ZO₂ and hydrate H₂ZO₃
• ZO is slightly soluble in water, ZO₂ moderately soluble and H₂ZO₃ very soluble
• H₂ZO₃ is a weak acid in solution
• UV levels are high even at the surface

Answer these questions about Z:

1. What are the oxidation numbers of all the species?
2. Suggest a dry oxidation pathway for H₄Z =>ZO
3. Suggest a wet oxidation pathway for ZO => H₂ZO₃
4. Describe wet deposition and dry deposition sinks for ZO₂