Question

What is a redox reaction? If magnesium ribbon burns in air it produces a dazzling flame and forms white ash, magnesium is oxidized or reduced? Why?

Answer 1

Hint: We need to know that oxidation and Reduction are two processes that you need to know before solving this question. The loss of electrons and the corresponding increase in the oxidation state of a given reactant is called oxidation. The gain of electrons and the corresponding decrease in the oxidation state of a reactant is called reduction.

Complete answer:
We have to remember that a redox reaction is the one in which oxidation and reduction takes place simultaneously. All the redox reactions can be broken down into two different processes – a reduction process and an oxidation process. These reactions are oxidation-reduction chemical reactions in which the reactants undergo a change in their oxidation states. The substance getting reduced in a chemical reaction is known as the oxidizing agent, while a substance that is getting oxidized is known as the reducing agent. Now it is asked what happens when magnesium ribbon is burnt in air? When magnesium ribbon is burnt in the air, it combines with oxygen to form white powder magnesium oxide with the release of heat and light. It forms a white powder of magnesium oxide. Magnesium gives up two electrons to oxygen atoms to form this powdery product.
$2Mg+O_2\to 2MgO$
While looking at the chemical equation above it is clearly seen that magnesium is oxidized, as it forms magnesium oxide.

Note:
We need to remember that the substance (atom, ion, and molecule) that gains electrons and is thereby reduced to a low valency state is called Oxidizing agent. The substance that loses electrons and is thereby oxidized to a higher valency state is called a reducing agent.