Ammonium Phosphate

What is Ammonium Phosphate?

Ammonium Phosphate comprises the phosphate salt along with ammonium. It is a very unstable compound. The chemical formula of Ammonium Phosphate is given as (NH4)3PO4. Ammonium Phosphate is manufactured commercially while mixing phosphoric acid along with ammonia. Sometimes, it can also be formed while adding an excess amount of ammonia along with acid phosphate whose chemical formula is (NH4)2HPO4. Generally, commercial-grade ammonium phosphate can be obtained in the form of crystalline powders.

What is the Formula of Ammonium Phosphate?

The formula for Ammonium Phosphate is (NH4)3PO4. Some of the other names include triammonium phosphate and diazonium hydrogen phosphate.


Structure of Ammonium Phosphate

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Physical Properties of Ammonium Phosphate



Chemical Properties of Ammonium Phosphate

  • As stated earlier, since ammonium phosphate comprises of mixing ammonia and phosphoric acid, it gains instability during production:

(NH4)3PO4 → 3NH3 + H3PO4

Even though triammonium salt has an unstable nature, diammonium phosphate still holds an important position within the fertilizer industry. That being said, all the phosphate acids are divided into three categories.

1. Phosphoric acid and super phosphoric acid

2. Normal superphosphate and triple superphosphate

3. Ammonium phosphate in granular form

  • Ammonium phosphate can readily react with lead nitrate, which results in the formation of ammonium nitrate and lead phosphate.

4(NH4)3PO4 + 3Pb(NO3)4 → Pb3(PO4)4 + 12NH4NO3

  • Anhydrous ammonia, along when it reacts with phosphoric acid, also results in the production of the ammonium phosphate.

NH3 + H3PO4 à NH4H2PO4

Ammonium Phosphate Uses

Down below is a list of some of the major use cases of ammonium phosphate:

  • Ammonium phosphate is used as a leavening agent during the process of baking

  • Its interaction with heat, results in instant evaporation without leaving any residue of ammonia

  • Due to the ability of rapidly dissolving and becoming soluble, ammonium phosphate works as an effective fertilizer. It has two crucial elements embedded in them, the ammonium and phosphate, both of which are highly beneficial to the plants

  • It also works great as a plant revitalizer

  • Ammonium phosphate can also be used as a great ingredient for dry chemical extinguisher

Solved Questions

Problem 1

If a sample of Ammonium phosphate (NH4)3PO4 has 3.18 moles of hydrogen atom. Then what is the number of moles available for oxygen atoms within the solution?

1) 0.265

2) 1.06

3) 0.795

4) 3.18


As we know that the molar mass of (NH4)3PO4 is 149 grams.

Within the same, contains 12 g of H

So for 3.18 moles, i.e. 3.18 grams of H, the total number of moles of ammonium phosphate:

12149×3.18​=39.5gm (NH4)3PO4

We know that 149 grams of (NH4)3PO4 contains 64g of oxygen

So, for 39.5 grams of (NH4)3PO4 it will contain 14964×39.5​g of oxygen.

                                                                                  =16.96 gm oxygen

So, 16.96 grams of oxygen is present

Converting it into moles, we get, 1616.96 = 1.06 moles of O

So, the right answer is option 2.

Problem 2

If 6 moles of H are present in a sample of (NH4)3PO4, what is the number of moles of oxygen atom? Answer the question without converting the moles into grams.

1)     6

2)     4

3)     2

4)     1


We know that in ammonium phosphate:

The total number of H atoms: 12

Total number of O atoms: 4

We know that the ratio of atoms and moles remains the same

So, 12/4 = 6/X

Or, X = 2

So, the total number of moles of oxygen is 2

FAQ (Frequently Asked Questions)

1. What is the Difference between Ammonia and Ammonium?

Ammonia, with its chemical formula of NH3, is a neutral substance. It doesn’t have any electrical change. On the contrary, Ammonium is positively charged. The ammonia compound consists of one nitrogen alongside three hydrogen atoms. Ammonium, on the other hand, consists of another hydrogen atom, resulting in a +1 in charge. So, on an atomic level, they are two different elements.

Both ammonia and ammonium can also be differentiated based on the pH level when mixed with water. Ionic strength and temperature are also some of the influential factors for ammonia. The un-ionized ammonia is deemed to be harmful to aquatic animals, while ammonium doesn’t show any such trait.

The chemical equation between ammonia and ammonium is given by:

NH 3 + H2O <-> NH 4 + + OH -

With a lower pH, the reaction shifts rightward, whereas a higher pH drives the equation to the left side. In room temperature, the pH is generally lower than 6. Thus, the proportion of ammonium N along with ammonia N remains unbalanced. While NH3 remains lower, the concentration of NH 4+ increases exponentially.

2. How is Ammonium Phosphate Soluble in Water?

Before figuring out its solubility, one needs to understand what is the chemical formula for ammonium phosphate along with its structure. It is an ammonium salt of orthophosphoric acid, which makes it a highly unstable compound and easy to react with. When ammonium phosphate is added in water, the acidic phosphate is formed, leaving ammonia behind. The reaction is what makes ammonium phosphate soluble in water. It is the sole reason, due to which (NH₄)₃PO₄ is used as a fertilizer.