What is the oxidizing agent in the following reaction?3 PbO (s) + 2 NH₃ (aq) → N₂ (g) + 3 H₂O (l) + 3 Pb (s)

Which element is being reduced in the following reaction? 

Cr₂O₇^2- + 3 HNO₂ + 5 H⁺ → 2 Cr³⁺ +  3NO₃^- + 4 H₂O

Identify the oxidizing agent and reducing agent from the following redox reaction. 

Ba (s) + Cl₂ (g) → BaCl₂ (aq)

Which element is oxidized and which is reduced in the following reaction?

Hg (aq) + HgCl₂ (aq) → Hg₂Cl₂

Which of the following represents an oxidation-reduction reaction? 

I. PCl₃ (aq) + Cl₂ (g) → PCl₅ (aq) 

II. 2 AgNO₃ (aq) + Cu (s) → Cu(NO₃)₂ (aq) + 2 Ag (s) 

III. CO₂ (g) + 2 LiOH (aq) → Li₂CO₃ (aq) + H₂O (l)

IV. FeCl₂ (aq) + 2 NaOH (aq) → Fe(OH)₂ (aq) + 2 NaCl (aq) 

In the Brønsted–Lowry concept of acids and bases, acid– base reactions are viewed as proton-transfer reactions. The stronger the acid, the weaker is its conjugate base. If we were to think of redox reactions in a similar way, what particle would be analogous to the proton? Would strong oxidizing agents be analogous to strong acids or strong bases? [Sections 20.1 and 20.2]

(b) On which side of an oxidation half-reaction do the electrons appear?

Indicate whether each of the following statements is true or false: (c) If there are no changes in the oxidation state of the reactants or products of a particular reaction, that reaction is not a redox reaction.