# Chemical Reactions : Agents of Oxidation & Reduction Quiz

Quiz
*Theme/Title: Agents of Oxidation & Reduction
* Description/Instructions
Oxidation-Reduction reactions (also called “redox” reactions) are reactions that involve a shift of electrons between reactants. Oxidation is complete or partial loss of electrons or gain of oxygen. Reduction is complete or partial gain of electrons or loss of oxygen. The substance in a redox reaction that loses electrons is called the reducing agent. The substance that gains electrons is called the oxidizing agent. In every redox reaction, even those that produce covalent products, there is an oxidizing agent and a reducing agent. An increase in oxidation state denotes oxidation and a decrease denotes reduction.

Note: A caret (^) indicates an exponent.

Example: Mg^+2 + S^-2 = MgS

Magnesium donates its two electrons to sulfur, so magnesium is the reducing agent and sulfur is the oxidizing agent. The magnesium ion and the sulfide ion combine to produce magnesium sulfide.