Which is the strongest reduction agent?

• A. Zn (s)
• B. Cr (s)
• C. H₂ (g)
• D. Fe²⁺ (aq)

When considering the strongest reducing agent among the options provided, we need to look at their ability to donate electrons. A reducing agent is a substance that loses electrons and reduces another substance in a chemical reaction.

Comparison of Options

• Zn (s): Zinc is a good reducing agent, commonly used in various reactions.
• Cr (s): Chromium can also act as a reducing agent, but it is less common in simple reactions.
• H₂ (g): Hydrogen gas is a strong reducing agent, especially in reactions with metals and metal oxides.
• Fe²⁺ (aq): Iron in the +2 oxidation state can act as a reducing agent, but it is generally weaker compared to the others listed.

Identifying the Strongest Agent

Among these, H₂ (g) is typically considered the strongest reducing agent. It readily donates electrons and can reduce many substances effectively.

In summary, the answer to your question is H₂ (g).