Properties of Potassium Dichromate

Potassium Dichromate has a variety of properties which are classified into physical and chemical properties. The physical and chemical properties of Potassium Dichromate are described below:

Physical Properties of Potassium Dichromate

The physical properties of Potassium Dichromate are Tabulated below:

Chemical Properties of Potassium Dichromate

The chemical Properties of K₂Cr₂O₇ can be best understood in the terms of chemical reaction it undergoes. Hence, the chemical reactions of Potassium Dichromate are mentioned below:

Reaction due to Heat

On heating, Potassium Dichromate decomposes to give out potassium chromate with the evolution of oxygen (O₂) gas. The chemical reaction involved is as follows:

4 K₂Cr₂O₇ → 4K₂CrO₄ + 2Cr₂O₃ + 3O₂

Oxidation Reaction

Being an oxidizing agent, each mole of potassium dichromate liberates three atoms of oxygen when reacted with dilute H₂SO₄, this reaction is illustrated below:

K₂Cr₂O₇ + 4H₂SO₄ → K₂SO₄ + Cr₂ (SO4)₃+ 4H₂O + 3(O)

Reaction with Alkalies

When Potassium Dichromate reacts with alkalies, potassium chromate is formed due to which the orange-red colour of K₂Cr₂O₇ changes into a yellow colour. It is represented by the following chemical reaction:

K₂Cr₂O₇ + 2KOH → 2K₂CrO₄ + H₂O

This yellow-coloured potassium chromate changes back to orange-red coloured potassium dichromate when acidified. The reaction involved here is:

2K₂CrO₄ + H₂SO₄ → K₂Cr₂O₇ + K₂SO₄ + H₂O

This process of conversion of potassium dichromate into potassium chromate and then conversion of potassium chromate back to potassium dichromate is due to equilibrium between Cr₂O₇^2- ions and CrO₄^2- ions.

Cr₂O₇^2- + H₂O ⇋ 2CrO₄^2- + 2H⁺

Acidified Potassium Dichromate

Potassium dichromate solution can be acidified by adding dilute sulphuric acid along with a few drops of the aldehyde or ketone. Acidified Potassium Dichromate can produce sulphur, potassium sulphate, chromium(III) sulphate, and water on reaction with hydrogen sulphide. On reaction with SO₂ the orange solution of acidified Potassium Dichromate turns green due to the formation of a green colour compound Cr₂(SO₄)³.

Potassium Dichromate is a chemical compound mainly used as an oxidizing agent. The chemical formula of Potassium Dichromate is represented as K₂Cr₂O₇. It is a hexavalent chromium compound having a bright red-orange color. It serves as an oxidizing agent in various industrial and laboratory applications. It is used to manufacture products such as matches, glass, ceramics, etc.

In this article, we will thoroughly study What is Potassium Dichromate, its structure, its preparation, and its wide range of applications.