13.Identify the oxidizing and reducing agent: 3CuS + 8HNO 3 ---> 3 CuSO 4 + 8NO + 4H 2 O 14. Solution We know that oxidizing agent : They are the compound who oxidises the other compound. and reducing agent : They are the compound who reduces the other compound. thus for the reaction 3 CuS + 8 HNO3 ---> 3 CuSO4 + 8 NO + 4 H2O we have In CuS , S-atom is going form oxidation state 2- to 6+ means it is being oxidised and thus CuS is a reducing agent and In HNO3 , N-atom is going form oxidation state 5+ to 2+ means it is being reduced and thus HNO3 is an oxidising agent..