Orthophosphoric Acid and Dichrometry: An In-Depth Exploration

Discover the versatile applications of orthophosphoric acid, from rust removal to agriculture, food, pharmaceuticals, and construction. Learn about its properties, usage, and essential safety precautions for handling this compound.

September 02, 2022

As a layman, you might not be aware of the composition and the meaning of orthophosphoric acid. It is same as the phosphoric acid with no difference at all.

Being a weak acid, it is not so harmful to you while handling it. But you need to remain cautious since it might have a mild reaction if you are a bit careless.

Phosphate rocks are the initial source to obtain this acid in its raw form. But the purest form can be attained from white phosphorous in industries with the help of various chemical processes and refinement steps.  

Properties of this acid

Phosphoric acid is a transparent crystalline solid with the chemical formula H3PO4. To your surprise, you will be amazed to know that it is present in your teeth and bones and stimulates metabolic processes.

Aside from the solid form, orthophosphoric acid is also present in a liquid state that is clear, non-volatile, and colourless.

Its popular usage areas

Several industries keep this acid in stock as it has myriad uses in products that we regularly use. 

Some of the prime areas where Phosphoric acid is mainly used are mentioned below for your knowledge.

1. Removing rust
The industries catering to iron and steel use this acid to remove rust from it. Initially, when it is applied to the metal, the iron oxide that is reddish brown is converted to ferric phosphate which is a black-coloured compound. 

Once this chemical reaction takes place and the colour changes, the rust is smoothly removed by scrubbing the surface of the iron.

2. Food and beverage

This acid is also used as an additive in various food products. Apart from this, it is considered to be an acidulant to prevent fungi and bacteria formation in beverages and emulsifying salts and baking powders. 

If you are engaged in preparing jams, processed meats, and cereal bars, then apply it as it is an acid regulator.

3. Agriculture

You may come across many news articles where it is specifically stated that almost 90% of orthophosphoric acid is procured by the fertilizer manufacturing industry for producing high-quality fertilizer. 

Many animal and poultry feed incorporates it as an additive and flavouring agent in such food.

4. Pharmaceutical industry

Another striking fact about its usage is that it is widely used in teeth whiteners and mouth-washing liquids. 

Many dentists prefer this solution for cleaning the teeth and etching purposes. If you regularly intake anti-nausea medicines then you will know that it is one of the components in such medicines. 

Other uses

Orthophosphoric acid is a common element used in fuel cells or oxyhydrogen generators as an electrolyte. 

Many factories engaged in detergents use it for preparing synthetic detergents. Moreover, it is also utilized to treat water and metals.

The construction industry swears by its applicability in removing mineral deposits, cement smears, and hard water stains. 

For the production of activated carbon products, this acid acts as an oxidizing agent. In sugar industries, it is used as a degumming agent.

Safety measures

Orthophosphoric acid is not as harmful as compared to concentrated nitric or sulphuric acid. 

But it may pose a challenge for you if you come in direct contact with this acid in its concentrated form which can cause skin irritation and affect your mucous membrane.

Since, it is less corrosive and non-combustible in liquid and solid form, hence, less toxic. Bus as a precaution, you should always refrain from inhaling it as it may be fatal for you. 

Hence, from the above discussion, you have got a fair idea about the composition and practical usage of orthophosphoric acid.

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