Magnesium reactivity with water

When prepared by direct reaction of the elements, magnesium hydride is stable in air and only mildly reactive with water. 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Reacts with zinc, aluminum, magnesium, and their alloys reaction is not violent Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Aluminum metal, the next element to the right in the same row as sodium and magnesium in the periodic table, has an even lesser tendency to lose electrons, even though it does lose electrons to become the aluminum ion, Al1. Its reactivity with water is almost nil ... 

Class D fires are pretty rare outside of specific chemical laboratories or workplaces. Some industrial processes that involve very hot metals such as aluminum or magnesium can lead to a fire if water contacts these metals. In labs, we often use elemental sodium or lithium and these are very reactive with water. Compounds called hydrides are also very reactive and will catch fire upon contact with water. Class D fires are called active metal fires. 

The Barbier reaction is that between an alkyl halide and a carbonyl compound in the presence of magnesium (Barbier, 1898). In Barbier-type reactions, an organometallic intermediate species is supposed to be produced in the presence of the substrate. As this organometallic intermediate is usually highly reactive with water, Barbier-type reactions were previously conducted after careful exclusion of water. 

Magnesium is reactive with water and generates hydrogen according to the... 

Magnesium. As it is well-known, electrodeposition of magnesium from aqueous solution is difficult due to its reactivity with water. In this sense, Bakkar and Neu-bert have investigated the electrodeposition of Zn onto several Mg alloys in different euteetie mixtures (ChCl/EG, ChCl/Urea, ChCl/MAc and ChCl/Gly)." After eomparing the efficiency of these DESs, ChCl/Urea was found to be the most suitable medium for the electrodeposition of Zn on Mg." ... 

Metals — Several metals react with water and air with the extent of reactivity being dependent upon the physical state of the metal. The highly reactive metals such as lithium, sodium, and potassium are pyrophoric (i.e., they ignite spontaneously in air without an ignition source). In contrast, the less reactive metals such as magnesium, zirconium, titanium, aluminum, and zinc are highly pyrophoric only as dusts. 

Caution Potassium is highly reactive. Although it may be handled safely in air if it is covered with a hydrocarbon solvent such as heptane or mineral oil, it will spark and ignite flammable organic vapors on contact with water. The magnesium formed in this reaction is highly reactive and pyrophoric (Note 1). Accordingly, Parts C and D of this procedure should be carried out behind a safety shield. 

Water Cooling Smothering Dilution Exposure Available Very low cost Not for Class C electrical fires Freezes at 32°F (0°C) Reactive with some material, e.g., sodium, magnesium Cannot extinguish low flash point materials... 

Magnesium is a very reactive metal and makes an excellent fuel under the proper conditions. It is oxidized by moist air to form magnesium hydroxide, Mg(OH) 2, and it readily reaets with all acids, including weak species such as vinegar (5% acetic acid) and boric acid. The reactions of magnesium with water and an acid (HX) are shown below ... 

The alkali and alkaline earth metals - such as sodium, potassium, barium, and calcium — would make excellent high-energy fuels, but, except for magnesium, they are too reactive with moisture and atmospheric oxygen. Sodium metal, for example, reacts violently with water and must be stored in an inert organic liquid, such as xylene, to minimize decomposition. 

The moderately reactive metals, magnesium, zinc and iron, react slowly with water. They will, however, react more rapidly with steam (Figure 10.3). In their reaction with steam, the metal oxide and hydrogen are formed. For example, magnesium produces magnesium oxide and hydrogen gas. 

---