Question

The following is an oxidation half reaction:

2Mg → 2Mg^+2


Although their masses are balanced, their charges are not. The number of electrons that must be added to the right side of the half reaction to adjust or balance their charges is:

Answer 1

2e⁻

Step-by-step explanation:

Oxidation-reduction reactions involve the transfer of electrons.

Redox Reactions

Oxidation-reduction reactions, often shortened to redox, have an oxidation and reduction half-reaction. In the oxidation half-reaction, a substance loses electrons. This means that the charge of the substance will increase or become more positive. Additionally, in the reduction half-reaction, the substance will gain an electron. This causes the charge to decrease. We can tell that the reaction above is oxidation because the charge of Mg increases.

Balancing a Reactions

In order to balance the charges in a simple redox reaction, we need to add electrons to one side. Since this is the oxidation half-reaction, we know that the electrons will be a product of the reaction. Remember that in oxidation reactions, electrons are lost. Additionally, the charge on the left is 0 and the charge on the right is 2. So, we need to add 2 electrons to the right to balance the charge.

• 2Mg → 2Mg²⁺ + 2e⁻

Now, the charge on both sides is 0. Thus, this is the balanced half-reaction.