What is the Reaction between Mg and NaOH?

Read this to learn the explanation to the question of what is more reactive sodium or magnesium as we discuss the reaction between Mg and NaOH.

Introduction:

Before we get into our topic of what is more reactive sodium or magnesium, let us first quickly review the related theory so that it will make the below explanation clearer. Reactivity is the capacity of a material to interact chemically with another substance, when two or more chemicals are physically combined or come into touch with one another, reactivity is happening in between them. To put it in definition, it is the proportionate ability of a radical, atom, or molecule to interact chemically with another entity which also can be an atom, radical, or molecule.

The two elements in question, Sodium (Na) and Magnesium (Mg) are both similar in terms of their nature being metallic elements are placed in the third-period of the periodic table but other than these two aspects, they are quite indifferent. Apart from their reactivity, other noticeable differences are their physical properties in which sodium is quite soft while Magnesium isn’t. It also has a higher melting point as compared to sodium which indicates that it has more molecular and thermal stability in its molecular structure.

What is more reactive sodium or magnesium & why?

As mentioned before, both elements are metals with quite different properties. However, there is another significant difference between the two, which is their reactivity. Since, both tend to lose electrons and become Na⁺ and Mg²+ ions when entering another molecular structure, the rate at which they do so is different for both of them.

Sodium is more reactive meaning that it readily reacts with other elements (when conditions are right for a reaction) and Magnesium on the other hand is moderately reactive. The reason behind this is the difference in electron configuration between the two and the greater ease of sodium to lose its electrons as compared to Magnesium.

To explain this behavior, it should be noted that magnesium contains two electrons and more than one proton at the outermost energy level (valence shell). On the other hand, its counterpart has only one electron in its outer shell. This configuration difference indicates that magnesium has a stronger nucleus-electron attraction than sodium does. As a result, magnesium is less reactive than sodium which can easily give away its electron due to less force being exerted from its nucleus.

The Reaction between Mg and NaOH

If there are conditions in which magnesium and NaOH are excited in such a way that will enable magnesium to remove sodium from its hydroxide ion then the following reaction would happen:

 Mg + 2NaOH → Mg(OH)

But in reality, this doesn’t happen. The reason behind this links back to the reactivity difference explained before. Magnesium has less reactivity as compared to sodium and cannot push it from the NaOH molecule, so no reaction will happen between the two participants in this reaction.

Another explanation behind this is that a metal needs to be amphoteric (a feature of an element to act as both acid and base) to react with a sodium hydroxide solution. Except for Beryllium, all alkaline earth metals including magnesium are not amphoteric but just basic. This also explains no reaction between the sodium hydroxide and magnesium metal. This metal will react with any acid to take away its hydrogen atom but won’t do any activity against the OH ion when it comes across NaOH.

This property of magnesium is often considered in its alloys where it shows resistance when exposed to various alkaline solutions apart from it being extremely lightweight. Another application of Magnesium showing resistance towards NaOH is in the magnesium electrodes which are used in conjunction with other alkaline electrolytes. Here, these electrodes can last much longer and give a stable performance thanks to magnesium resistance in the alkaline solution.

Conclusion:

In this article, we went through all the concepts and explanations to answer the question “What is more reactive sodium or magnesium” and how does magnesium react with sodium hydroxide?  The reactivity difference halts the reaction between Mg and NaOH and finds many applications in the current industry.