(A) if both sentences are true, (B) if both sentences are false, (C) if the first sentence is true but the second is false, and (D) if the first sentence is false but the second is true. 1. An acidic and a basic solution may be used to balance the redox reaction when the oxidation number method is employed.  The final step in balancing redox reactions using the oxidation number method is to balance by inspection. 2. In the oxidation number method of balancing redox reactions, there is a need to add water and hydroxide ions on both sides of the chemical reaction. The oxidation state of oxygen is always (-2) except for peroxides.  3. In the half-reaction method of balancing redox reactions, the reaction is divided into three half-reactions. In a redox reaction, the oxidation number of iron changed from +2 to +3; thus, sulfur is an oxidizing agent.

(A) if both sentences are true,
(B) if both sentences are false,
(C) if the first sentence is true but the second is false, and
(D) if the first sentence is false but the second is true.

1. An acidic and a basic solution may be used to balance the redox reaction when the oxidation number method is employed. 

The final step in balancing redox reactions using the oxidation number method is to balance by inspection.

2. In the oxidation number method of balancing redox reactions, there is a need to add water and hydroxide ions on both sides of the chemical reaction.

The oxidation state of oxygen is always (-2) except for peroxides. 

3. In the half-reaction method of balancing redox reactions, the reaction is divided into three half-reactions.

In a redox reaction, the oxidation number of iron changed from +2 to +3; thus, sulfur is an oxidizing agent.

4. In a redox reaction, the oxidation number of iron changed from +2 to +3; thus, sulfur is a reducing agent. 

In a redox reaction, the oxidation number of nitrogen was unchanged; thus, nitrogen is an oxidant.

5. In a redox reaction, the reducing agent is oxidized and it gains electrons.

In a redox reaction, the oxidizing agent is reduced and it gains electrons.