SCH4C-Chemistry Lesson 1 3. Consider the following reaction for silver tarnishing: 3Ag2S(s) + 2Al(s) â 6Ag(s) + AhS3(s) a. State the oxidation number for each element in the reaction. (3 marks) b. Identify the oxidized reactant and the reduced reactant. (2 marks) 4. The following reactions are involved in the formation of acid rain (as learned in lesson 16). Use oxidation numbers to identify which of these reactions are REDOX reactions. a. b. c. 2SO2(g) + O2(g) â 2SO2(g) 3NO2(g) + H2O(I) â 2 HNO3(aq) + NO(g) SO2(g) + H2O ) â H2SO3(aq)