Identify the oxidizing agent and reducing agent from the following redox reaction. 
Ba (s) + Cl₂ (g) → BaCl₂ (aq)

• A. Ba: oxidizing agent; Cl₂ reducing agent
• B. Ba: reducing agent; Cl₂ oxidizing agent

Answer: (B)

Verified step by step guidance

1. Understand the concept of oxidation and reduction: Oxidation involves the loss of electrons, while reduction involves the gain of electrons. In a redox reaction, the oxidizing agent is the substance that gains electrons (is reduced), and the reducing agent is the substance that loses electrons (is oxidized).
2. Identify the oxidation states of the elements before and after the reaction: In the given reaction, Ba starts as a solid metal (Ba) with an oxidation state of 0, and Cl2 starts as a diatomic molecule (Cl2) with an oxidation state of 0 for each Cl atom.
3. Determine the changes in oxidation states: After the reaction, Ba becomes part of BaCl2, where it has an oxidation state of +2, indicating it has lost electrons. Cl2 becomes part of BaCl2, where each Cl atom has an oxidation state of -1, indicating it has gained electrons.
4. Assign the roles of oxidizing and reducing agents: Since Ba loses electrons, it is oxidized and acts as the reducing agent. Since Cl2 gains electrons, it is reduced and acts as the oxidizing agent.
5. Conclude the identification: Ba is the reducing agent because it donates electrons, and Cl2 is the oxidizing agent because it accepts electrons.