Why does hot steam produce MgO instead of Mg(OH)2?

Question

Background research

Magnesium hydroxide exists naturally as brucite (source: wiki)
Passing hot steam over magnesium produces magnesium oxide (source: Edexcel's June 2014 Unit 2 exam (CH02_01): question 18)

Question

Why doesn't magnesium hydroxide form when treated with hot steam, instead of magnesium oxide?

DrMoishe Pippik · Accepted Answer · 2018-04-20 01:12:18Z

9

There are two steps in the process:

$\ce{Mg + H2O -> MgO + H2}$

and

$\ce{MgO + H2O <-> Mg(OH)2}$

The equilibrium point in the second step is dependent on the temperature. See file Equilibrium Assemblages for more information.

answered Mar 16, 2015 at 5:58

DrMoishe Pippik

35.3k1 gold badge39 silver badges78 bronze badges

$\begingroup$ The chemical equation has to be balanced $\endgroup$
– Arvin Kushwaha
Commented Apr 19, 2018 at 17:56

Add a comment |

Arvin Kushwaha · Accepted Answer · 2016-05-22 02:45:17Z

1

$\ce{Mg(OH)2}$ decomposes at high temps into $\ce{MgO}$ and $\ce{H2O}$. To be exact, 350 C

answered May 21, 2016 at 14:13

Arvin Kushwaha

4515 silver badges15 bronze badges

Add a comment |

2 Answers 2