Question

Write a balanced overall reaction given the unbalanced half-reactions.

rb →› rb ⁺
mg²⁺ 一 mg

Answer 1

To balance an overall reaction from unbalanced half-reactions, one must balance atom counts, balance charge with electrons, and then combine the half-reactions. An example of a balanced reaction is 2Rb(s) + MgCl2(s) → Mg(s) + 2RbCl(s), which obeys the law of conservation of mass and charge.

Step-by-step explanation:

To write a balanced overall reaction given unbalanced half-reactions, we need to follow these steps:

• Balance the atoms other than oxygen and hydrogen in each half-reaction.
• Balance the oxygen atoms by adding H2O.
• Balance the hydrogen atoms by adding H+.
• Balance the charges by adding electrons. For oxidation half-reactions, add electrons to the products side. For reduction half-reactions, add electrons to the reactants side.
• Combine the half-reactions and cancel out the electrons to get the overall balanced equation.

Let's take an example of the reaction between rubidium (Rb) and magnesium chloride (MgCl2). The half-reactions can be written and balanced as follows:

1. Rb → Rb+ + e- — This is an oxidation half-reaction.
2. Cl2 + 2e- → 2Cl- — This is a reduction half-reaction.

The balanced chemical equation for the reaction between rubidium and magnesium chloride is:

2Rb(s) + MgCl2(s) → Mg(s) + 2RbCl(s)

This equation is balanced in terms of both atoms and charge, which confirms the law of conservation of mass and charge.