Mg+H2O

The reaction between magnesium (Mg) and water (H₂O) can occur under certain conditions, producing magnesium hydroxide (Mg(OH)₂) and hydrogen gas (H₂). The overall reaction is as follows:

\[ \text{Mg (s)} + 2 \text{H}_2\text{O (l)} \rightarrow \text{Mg(OH)}_2\text{ (aq)} + \text{H}_2\text{ (g)} \]

However, magnesium reacts very slowly with cold water due to the formation of a thin layer of magnesium hydroxide that coats the metal, preventing further reaction. When magnesium is added to steam (hot water vapor), it reacts more readily:

\[ \text{Mg (s)} + \text{H}_2\text{O (g)} \rightarrow \text{MgO (s)} + \text{H}_2\text{ (g)} \]

In this case, magnesium oxide (MgO) and hydrogen gas (H₂) are produced.

If you're studying for exams, it might be useful to note the conditions under which magnesium reacts with water, the products formed, and the properties of these substances.