What Happens When H3PO3 Is Heated?

Are you curious to know what is happens when H3PO3 is heated? You have come to the right place as I am going to tell you everything about happens when H3PO3 is heated in a very simple explanation. Without further discussion let’s begin to know what is happens when H3PO3 is heated?

What Happens When H3PO3 Is Heated?

Heating substances can lead to a variety of chemical reactions, and when it comes to phosphorous acid (H3PO3), it is no exception. Phosphorous acid is a chemical compound with the formula H3PO3. When subjected to heat, it undergoes a decomposition process, resulting in the formation of different products. In this blog, we will explore what happens when H3PO3 is heated and delve into the chemistry behind this transformation.

The Composition Of H3PO3

Phosphorous acid (H3PO3) is an inorganic compound containing phosphorus, hydrogen, and oxygen. It is a diprotic acid, which means it can donate two protons (H+) in aqueous solutions. Its chemical formula is H3PO3, reflecting the presence of three hydrogen atoms, one phosphorus atom, and three oxygen atoms.

Heating H3PO3: Phosphorous Acid Decomposition

When phosphorous acid (H3PO3) is heated, it undergoes a decomposition reaction, resulting in the formation of different products. This reaction can be described as follows:

H3PO3 (phosphorous acid) → H3PO4 (phosphoric acid) + PH3 (phosphine gas)

  1. Formation of Phosphoric Acid (H3PO4): One of the products of heating H3PO3 is phosphoric acid (H3PO4). This is a stronger acid compared to phosphorous acid, and it contains four oxygen atoms bonded to phosphorus. The decomposition process involves the loss of water molecules from H3PO3, leading to the formation of H3PO4. The reaction can be summarized as follows:

2H3PO3 (Phosphorous Acid) → H3PO4 (Phosphoric Acid) + H2O (Water)

  1. Generation of Phosphine Gas (PH3): Another significant product of heating H3PO3 is phosphine gas (PH3). Phosphine is a colorless, flammable, and toxic gas. The formation of phosphine occurs due to the reduction of phosphorus in the H3PO3 molecule, driven by the heat. The chemical reaction can be represented as follows:

4H3PO3 (Phosphorous Acid) → 3H3PO4 (Phosphoric Acid) + PH3 (Phosphine Gas)

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Importance Of Phosphoric Acid And Phosphine

Phosphoric acid (H3PO4) and phosphine gas (PH3) have diverse applications in various industries and fields:

  1. Phosphoric Acid (H3PO4): Phosphoric acid is used in the food industry as an acidulant in soft drinks, jams, and other processed foods. It is also employed in the production of fertilizers, detergents, and as a rust inhibitor. Moreover, it is a crucial component in the synthesis of phosphate salts, which are used in water treatment, metallurgy, and various chemical processes.
  2. Phosphine Gas (PH3): Phosphine gas has applications in the semiconductor industry, where it is used in the production of integrated circuits. It is also utilized as a fumigant for stored grain and as a reducing agent in chemical reactions. Additionally, phosphine is a valuable dopant in the manufacturing of semiconductor materials.


Heating phosphorous acid (H3PO3) initiates a decomposition reaction that leads to the formation of phosphoric acid (H3PO4) and phosphine gas (PH3). Both of these products have wide-ranging applications in various industries, making the understanding of this reaction and its products essential for chemistry and industrial processes. It is a testament to the fascinating world of chemical reactions and the practical applications they offer.


What Happens If H3PO3 Is Heated?

H3PO3, on heating, undergoes disproportionation reaction to form PH3 and H3PO4. The oxidation numbers of P in H3PO3, PH3, and H3PO4 are +3, −3, and +5 respectively. As the oxidation number of the same element is decreasing and increasing during a particular reaction, the reaction is a disproportionation reaction.

What Happens When H3po4 Is Heated?

When H3PO4 is heated it gives 2 products-P2O5 and H2O.

What Is The Equation For H3PO3 Heated?

H3PO3 Δ→ PH3 + H3PO4Orthophosphorous Phosphine Orthophosphoric.

What Is The Complete Reaction Of H3PO3?


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