Ammonium Phosphate Formula – Structure, Properties, Uses, Sample Questions

Ammonium Phosphate is a salt that is prominently used in fertilizers. It is a composition of ammonia and phosphoric acid. In this article, we will discuss its formula, structure, physical properties, chemical properties, uses, preparation methods, harmful effects, and safety precautions that are to be taken. 

Ammonium Phosphate formula

Ammonium Phosphate is an inorganic compound that is a composition of ammonia and phosphoric acid. It is colorless and an unstable salt. It is found in crystalline form and is soluble in water. The chemical formula of Ammonium Phosphate is (NH₄)₃PO₄. 

Ammonium ion has a positive charge (1⁺) and phosphate ion with a charge (3^–). After balancing the charge the formula obtained is (NH₄)₃PO₄. Its structure, properties use, and preparation methods are discussed in the following article. 

Structure of Ammonium Phosphate 

The chemical formula of Ammonium Phosphate is (NH₄)₃PO₄. Its molar mass is 149.09g/mol.

Physical Properties of Ammonium Phosphate

• The molecular formula of Ammonium Phosphate is (NH₄)₃PO₄.
• Ammonium Phosphate is a crystalline solid with a white appearance.
• It has odour of ammonia.
• It is soluble in water and has a pH range is 4-4.5.
• Its Melting Point is 155^oC and boiling point is 130^oC.
• Its density is 1.619 g/cm³ with molar mass 149.09 g/mol.

Chemical properties of Ammonium Phosphate

• Ammonium Phosphate goes through a decomposition reaction to give products such as phosphoric acid and ammonia. Toxic gases are also released in this reaction. The chemical reaction is 

(NH₄)₃PO₄   →   3NH₃ + H₃PO₄

• Ammonium Phosphate Reacts with zinc nitrate to form the products zinc phosphate and ammonium nitrate.

Zn(NO₃)₂  +  2(NH₄)PO₄    →   Zn₃(PO₄)₂ + 6NH₄NO₃

•  When ammonium phosphate reacts with lead nitrate, a double displacement reaction takes place and lead phosphate and ammonium nitrate are formed.  

3Pb(NO₃)₂ + 2(NH₄)₃PO₄   →   Pb(PO₄)₂ + 6NH₄NO₃ 

Preparation of Ammonium Phosphate 

• Phosphoric acid and ammonia solution are treated to get ammonium phosphate. The reaction is as follows,  

3NH₃  + H₃PO₄   →   (NH₄)₃PO₄

• Neutralization reaction takes place when ammonia and phosphoric acid are reacted to get mono ammonium phosphate as the product. It is further reacted to ammonia again to get diammonium phosphate. The chemical reactions are

NH₃ + H₃PO₄  → NH₄H₂PO4

NH₄H₂PO₄ + NH₃  → (NH₄)₂HP₄

Harmful effects and safety measures for Ammonium Phosphate

It is poisonous and toxic if it is absorbed. It raises ammonia levels in the blood and may damage internal organs. It may also cause diarrhea and eye and skin irritation may also occur. 

Always wear gloves to avoid direct contact with the skin. Always wear special protective clothes along with protection glasses and masks. If handling the chemical, always wash your hands thoroughly. Washing all the safety equipment and clothes is a must before reusing them. Avoid inhaling the fumes or gas of the chemical.

Uses of Ammonium Phosphate

• As Ammonium Phosphate is rich in elemental nitrogen, it is used in certain fertilizers for the plants.
• It is used in dry chemical fire extinguishers as an important ingredient.
• It is used as a leavening agent in baking.

Sample Questions

Question 1: What are the compounds of Ammonium Phosphate?

Answer:

There are three different chemical compounds of Ammonium Phosphate. They all are formed by the reaction of ammonia and phosphoric acid. They are:

• mono ammonium phosphate (NH₄H₂PO₄)
• diammonium phosphate ((NH₄)₂(HPO₄))
• tri ammonium phosphate ((NH₄)₃PO₄)

Question 2: Are both ammonia and ammonium the same?

Answer: 

No, they are different. Ammonia has 1 nitrogen and 3 hydrogen atoms. Whereas ammonium has 1 nitrogen and 4 hydrogen atoms. Their chemical formulas are NH₃ and NH₄⁺ respectively. Ammonia is a weak base and un ionized. But ammonium is ionized. Ammonia has a very strong smell whereas ammonium is odorless.

Question 3: What happens when Ammonium Phosphate is heated?

Answer:

Ammonia and phosphoric acid were formed when (NH₄)₃PO₄ is heated. The chemical reaction is 

(NH₄)₃PO₄ → 3NH₃ + H₃PO₄

Question 4: What happens when Ammonium Phosphate is reacted with nickel(II) nitrate?

Answer: 

Nickel phosphate is formed as a precipitate along with ammonium nitrate when Ammonium Phosphate is reacted with nickel(II) nitrate. The chemical reaction is as follows:

(NH₄)3PO₄ + Ni(NO₃)₂ → NH₄NO₃(aq) + Ni₃(PO₄)₂ (ppt)

Question 5: What are the uses of Phosphoric Acid?

Answer:

The uses of Phosphoric Acid are-

• It is used to remove rust from metals like iron and steel. 
• It is used as an ingredient in teeth whiteners and mouth wash. It is also used to clean teeth.
• It also has a prominent use in personal care products.
• It is used as an additive in food. It is used in cheese, jams, and processed meat as an acidity regulator. 
• It is used in the agriculture industry as a fertilizer.