Magnesium Nitride and Water Reaction | Mg3N2 + H2O

Magnesium nitride (Mg3N2 ) reacts with water and form magnesium hydroxide (Mg(OH)2) white precipitate and ammonia gas. This reaction is used to prove that air contains nitrogen gas.

magnesium nitride and water reaction

Mg3N2 + H2O → Mg(OH)2 + NH3

Magnesium nitride and water react and form a white precipitate, magnesium hydroxide and ammonia gas. Magnesium hydroxide is not s soluble hydroxide in water. However due to existing hydroxyl ions in the aqueous solution, solution will become basic. Formed ammonia gas is a basic gas too and can be identified by several tests.

Magnesium nitride (Mg3N2)

Magnesium nitride is an inorganic compound which contains Magnesium and Nitrogen as elements. At room temperature and pressure, it is a pale yellow powder.

Balanced Equation of magnesium nitride and water reaction

Mg3N2(s) + 6H2O(l) → 3Mg(OH)2(s) + 3NH3(g)

According to the stoichiometry , 1 mol of Mg3N2 react with 6 mol of water and give 3 mole of Mg(OH)2 and 3 mol of NH3.

How do I conduct this reaction in the laboratory?

Here, I am going to explain how to prepare ammonia gas using magnesium metal. Be careful, when you conduct this experiment because ammonia is a toxic gas and be careful from burnings too.

Find a magnesium piece and burn it in the air. Magnesium oxide and magnesium nitride are given as products.

  • Mg + N2 → Mg3N2
  • Mg + O2 → MgO

Then add products to water. You can test ammonia gas which is released as a product from the reaction.

Because magnesium oxide is also with magnesium nitride, magnesium oxide also give magnesium hydroxide precipitate.

How to prove air contains nitrogen gas?

Conduct the same experiment which is explained above. Because ammonia gas is produced, there should be a nitrogen source when pre-reactions are occurred. But, we don't know what are the products given by the first reaction. But, I write them now to make easy the understanding of yours.

  • Mg(s) + N2(g) → Mg3N2(s)
  • Mg(s) + O2(g) → MgO(s)
  • Water does not have nitrogen atoms. Therefore, water cannot be a source for nitrogen.
  • Then, source of nitrogen should be air.

Is magnesium nitride soluble in water?

Magnesium nitride dissolves very well in water and reacts with water to produce magnesium hydroxide and ammonia gas. Magnesium hydroxide is a white colour precipitate. 

Formation of magnesium hydroxide precipitate when magnesium nitride reacts with water

Due to formation of white colour magnesium hydroxide precipitate, someone can say or see, as magnesium nitride is insoluble in water. But, truth is magnesium nitride is soluble in water.

Questions asked by students

Ask your question and find the answer free.

What is wrong about following sentences about magnesium nitride and water reaction?

  • Nitrogen's oxidation number is protected during the reaction.
  • A white colour precipitate is formed when products are given.
  • This reaction is a safe reaction to do.
  • Product solution will show pH values higher than 7.

Statement 3 is wrong. This reaction emits ammonia gas as a product. ammonia is a toxic gas and can harm people.

Will give a precipitate when magnesium nitride reacts with water? Is magnesium nitride soluble?

Yes. A white precipitate is formed when magnesium nitride is added to water. Therefore, magnesium nitride is soluble in water.

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