In redox reactions, which statement is true?

• A. They occur independently
• B. Only oxidation occurs
• C. They occur together
• D. Only reduction occurs

Answer: (C)

Redox reactions involve electron transfer between species. In any redox process, one substance is oxidized (loses electrons) and another is reduced (gains electrons); these two changes occur simultaneously because electrons must go somewhere. The statement that they occur together is the correct one because the oxidizing agent accepts electrons and is reduced, while the reducing agent donates electrons and is oxidized. A simple example is zinc metal reacting with copper(II) sulfate: zinc is oxidized to Zn2+ and releases electrons, which copper(II) ions gain to form copper metal. If oxidation happened without any reduction, there would be no sink for electrons; if reduction happened without any donor, electrons would appear from nowhere.