The chromic acid has a chemical formula that acts as a corrosive and oxidizing agent and is used for cleaning. Its uses are focused on the application of ceramic glazes as well as for dyeing glass. It is available for purchase for the chemical industry, allowing various applications, as it has the characteristic of beautifying brass.
What is Chromic Acid
It is an oxidizing and highly corrosive substance categorized as an oxyacid, a ternary combination made up of hydrogen, oxygen, and a non-metal element. Occasionally, a metal such as chromium, tungsten, vanadium, or manganese can be used since these metals act as non-metals when they have a high oxidation state.
Formed by sulfuric acid and potassium dichromate, it is known as “tetraoxochromic acid VI” or chromic acid.
Its applications range from polishing musical instruments and metal parts to commercial use for cleaning glass of organic residues, although it should be handled with care, following the safety data sheet instructions.
Contents
- 1 What is Chromic Acid
- 2 Properties, Characteristics, and Chemical Formula (Formulation)
- 3 Uses
- 4 Relation to Sulfuric Acid
- 5 Similarities with Perbromic Acid
- 6 Nomenclatures
- 7 Is it the same as Dichromate Acid or Potassium Dichromate?
- 8 Chemical Reactions with Other Compounds
- 9 Where to Buy Commercial Chromic Acid
Properties, Characteristics, and Chemical Formula (Formulation)
- Chromic acid formula: H2CrO4.
- Molar mass: 118.01 g/mol.
- Density: 1.2 g/cm3.
- Solubility: with water.
- IUPAC name: Chromic acid.
- Boiling point: 250 °C.
- Melting point: 197 °C.
- Form of presentation: liquid or crystals.
The commercial type can be purchased under the chromic acid nomenclature. Known worldwide by this name and also as “chromic acid,” it is interesting because it works with many materials. Its reaction is powerful, oxidizing and removing imperfections from metals it is applied to.
Uses
- Polishing brass.
- Removing organic residues.
- Cleaning glass.
- For impregnating ceramic glaze.
- For leather production.
- Paint manufacturing.
For cleaning glass or crystals, it is common to add ammonium or potassium dichromate. This makes it somewhat more manageable, although care must still be taken due to its toxicity, both when using it and when disposing of it.
In addition to potassium and ammonium dichromates, it can also be mixed to give chromic acid uses in cleaning with solid chromium trioxide or CrO3.
Relation to Sulfuric Acid
For its production, one of the most known acids is required, so sulfuric and chromic acids are linked for their applications in glazes and glass coloring.
Currently, there is a well-known solution called the sulfuric-chromic mixture or chromic acid-sulfuric acid. As its name indicates, it has an important sulfuric acid component (H2SO4).
Similarities with Perbromic Acid
It includes a type of potassium in its formulation, although it is not the same since its chemical structure is somewhat different. Perbromic acid is a reducing agent, but when used in dilutions, it also acts as a slow oxidizing agent, improving the effectiveness of perchloric acid. Alternatively, it can reduce the compound to chromium, which can result in tin chloride.
The similar characteristics are that they both belong to the strong acids and oxidizing agents group. Both compounds are highly corrosive, which requires handling them with safety, avoiding direct contact with the skin, mucous membranes, and also inhalation or ingestion. If damage occurs, health consequences can be very serious and irreparable.
Nomenclatures
- Traditional nomenclature: Chromic acid.
- Tetraoxochromic acid VI.
- Tetraoxochromate VI of hydrogen.
- Chromium trioxide.
Is it the same as Dichromate Acid or Potassium Dichromate?
Although its name can be confusing, they are different substances or chemical compounds. Dichromate acid is a salt derived from chromic acid.
One way to distinguish them at first sight is by their color. Chromates are yellow in most cases because they contain the CrO4(2-) ion. Dichromates are usually orange, with a stronger hue than chromates. Dichromate acid has the Cr2O7(2-) ion, which also gives it its color.
Chemical Reactions with Other Compounds
In the chemical industry, there is an aqueous dilution capable of removing alcohol. This is known as the “Jones reagent” and contains water + sulfuric acid and acetone.
This type of dilution oxidizes primary and secondary alcohols, as well as carboxylic acids and ketones. In most cases, it leaves unsaturated bonds intact.
Also, tetraoxochromic acid or chromium trioxide has uses and applications with pyridinium chlorochromate, pyridine, and chromyl chloride.
Where to Buy Commercial Chromic Acid
Due to its hazardous nature, its use is decreasing in favor of other more stable and less harmful substances. You can buy chromic acid in chemical product stores and industrial wholesalers dealing with corrosive agents and specific treatments for metals and glass.