Which of the following is true about a redox reaction?

• A. It involves the transfer of electrons between species.
• B. Redox reactions only occur in aqueous solutions.
• C. No change in oxidation states occurs during the reaction.
• D. Both oxidation and reduction occur in separate reactions, not simultaneously.

Answer: (A)

Verified step by step guidance

1. Understand the definition of a redox reaction: it is a chemical reaction involving the transfer of electrons between two species.
2. Recall that in a redox reaction, one species undergoes oxidation (loses electrons) and another undergoes reduction (gains electrons), so both processes occur simultaneously in the same reaction.
3. Recognize that redox reactions are not limited to aqueous solutions; they can occur in various phases including gases and solids.
4. Know that a key characteristic of redox reactions is the change in oxidation states of the elements involved, reflecting the electron transfer.
5. Conclude that the true statement about redox reactions is that they involve the transfer of electrons between species.